diff --git a/Gruntfile.js b/Gruntfile.js
index 46e1f26..1c330cc 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -31,12 +31,14 @@ module.exports = function(grunt) {
         fileExt = '.php',
         baseUnits = {},
         units = [
-            { unit: 'Mass',   base: 1, relative: 0, symbol: 'g', label: 'gram', prefix: '' }, 
-            { unit: 'Length', base: 1, relative: 0, symbol: 'm', label: 'meter', prefix: '' }, 
-            { unit: 'Area',   base: 1, relative: 0, symbol: 'm', label: 'meter', prefix: 'Square' },
-            { unit: 'Volume', base: 1, relative: 0, symbol: 'm', label: 'meter', prefix: 'Cubic' },
-            { unit: 'Volume', base: 1, relative: 1, symbol: 'l', label: 'liter', prefix: '' },
-            { unit: 'Amount', base: 1, relative: 1, symbol: 'mol', label: 'mole', prefix: '' },
+            { unit: 'Mass',     base: 1, relative: 0, symbol: 'g',  label: 'gram', prefix: '' }, 
+            { unit: 'Length',   base: 1, relative: 0, symbol: 'm',  label: 'meter', prefix: '' }, 
+            { unit: 'Area',     base: 1, relative: 0, symbol: 'm',  label: 'meter', prefix: 'Square' },
+            { unit: 'Volume',   base: 1, relative: 0, symbol: 'm',  label: 'meter', prefix: 'Cubic' },
+            { unit: 'Volume',   base: 1, relative: 1, symbol: 'l',  label: 'liter', prefix: '' },
+            { unit: 'Amount',   base: 1, relative: 1, symbol: 'mol',  label: 'mole', prefix: '' },
+            { unit: 'Pressure', base: 1, relative: 0, symbol: 'Pa', label: 'pascal', prefix: '' },
+            { unit: 'Pressure', base: 1, relative: 1, symbol: 'bar', label: 'bar', prefix: '' },
          ];
     phpTemplate = `<?php
 namespace PhpUnitConversion\\Unit\\<%= unit %>;
diff --git a/src/Unit/Pressure.php b/src/Unit/Pressure.php
new file mode 100644
index 0000000..6d5bf9b
--- /dev/null
+++ b/src/Unit/Pressure.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit;
+
+use PhpUnitConversion\Unit;
+use PhpUnitConversion\UnitType;
+
+class Pressure extends Unit
+{
+    const TYPE = UnitType::PRESSURE;
+
+    const BASE_UNIT = Pressure\Pascal::class;
+}
diff --git a/src/Unit/Pressure/AttoBar.php b/src/Unit/Pressure/AttoBar.php
new file mode 100644
index 0000000..f014fd2
--- /dev/null
+++ b/src/Unit/Pressure/AttoBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class AttoBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E-18;
+
+    const SYMBOL = 'abar';
+    const LABEL = 'attobar';
+}
diff --git a/src/Unit/Pressure/AttoPascal.php b/src/Unit/Pressure/AttoPascal.php
new file mode 100644
index 0000000..222e4c9
--- /dev/null
+++ b/src/Unit/Pressure/AttoPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class AttoPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E-18;
+
+    const SYMBOL = 'aPa';
+    const LABEL = 'attopascal';
+}
diff --git a/src/Unit/Pressure/Bar.php b/src/Unit/Pressure/Bar.php
new file mode 100644
index 0000000..0c37989
--- /dev/null
+++ b/src/Unit/Pressure/Bar.php
@@ -0,0 +1,16 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasFactor;
+use PhpUnitConversion\Unit\Pressure;
+
+class Bar extends Pressure implements Metric
+{
+	use HasFactor;
+
+	const FACTOR = 1E5;
+
+    const SYMBOL = 'bar';
+    const LABEL = 'bar';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/Barye.php b/src/Unit/Pressure/Barye.php
new file mode 100644
index 0000000..d140b19
--- /dev/null
+++ b/src/Unit/Pressure/Barye.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\Unit\Pressure;
+
+class Barye extends Pressure
+{
+	const FACTOR = 0.1;
+
+    const SYMBOL = 'Ba';
+    const LABEL = 'barye';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/CentiBar.php b/src/Unit/Pressure/CentiBar.php
new file mode 100644
index 0000000..6de23c8
--- /dev/null
+++ b/src/Unit/Pressure/CentiBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class CentiBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E-2;
+
+    const SYMBOL = 'cbar';
+    const LABEL = 'centibar';
+}
diff --git a/src/Unit/Pressure/CentiMetreOfMercury.php b/src/Unit/Pressure/CentiMetreOfMercury.php
new file mode 100644
index 0000000..3453684
--- /dev/null
+++ b/src/Unit/Pressure/CentiMetreOfMercury.php
@@ -0,0 +1,10 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+class CentiMetreOfMercury extends MilliMetreOfMercury
+{
+	const FACTOR = 1333.22387415;
+
+    const SYMBOL = 'cmHg';
+    const LABEL = 'centimetre of mercury';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/CentiMetreOfWater.php b/src/Unit/Pressure/CentiMetreOfWater.php
new file mode 100644
index 0000000..59eabc5
--- /dev/null
+++ b/src/Unit/Pressure/CentiMetreOfWater.php
@@ -0,0 +1,10 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+class CentiMetreOfWater extends MilliMetreOfWater
+{
+	const FACTOR = 98.0638;
+
+    const SYMBOL = 'cmH2O';
+    const LABEL = 'centimetre of water';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/CentiPascal.php b/src/Unit/Pressure/CentiPascal.php
new file mode 100644
index 0000000..6af141d
--- /dev/null
+++ b/src/Unit/Pressure/CentiPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class CentiPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E-2;
+
+    const SYMBOL = 'cPa';
+    const LABEL = 'centipascal';
+}
diff --git a/src/Unit/Pressure/DecaBar.php b/src/Unit/Pressure/DecaBar.php
new file mode 100644
index 0000000..de4f64a
--- /dev/null
+++ b/src/Unit/Pressure/DecaBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class DecaBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E1;
+
+    const SYMBOL = 'dabar';
+    const LABEL = 'decabar';
+}
diff --git a/src/Unit/Pressure/DecaPascal.php b/src/Unit/Pressure/DecaPascal.php
new file mode 100644
index 0000000..11e0356
--- /dev/null
+++ b/src/Unit/Pressure/DecaPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class DecaPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E1;
+
+    const SYMBOL = 'daPa';
+    const LABEL = 'decapascal';
+}
diff --git a/src/Unit/Pressure/DeciBar.php b/src/Unit/Pressure/DeciBar.php
new file mode 100644
index 0000000..1deb3ce
--- /dev/null
+++ b/src/Unit/Pressure/DeciBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class DeciBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E-1;
+
+    const SYMBOL = 'dbar';
+    const LABEL = 'decibar';
+}
diff --git a/src/Unit/Pressure/DeciPascal.php b/src/Unit/Pressure/DeciPascal.php
new file mode 100644
index 0000000..97e3204
--- /dev/null
+++ b/src/Unit/Pressure/DeciPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class DeciPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E-1;
+
+    const SYMBOL = 'dPa';
+    const LABEL = 'decipascal';
+}
diff --git a/src/Unit/Pressure/ExaBar.php b/src/Unit/Pressure/ExaBar.php
new file mode 100644
index 0000000..ba55f84
--- /dev/null
+++ b/src/Unit/Pressure/ExaBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class ExaBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E18;
+
+    const SYMBOL = 'Ebar';
+    const LABEL = 'exabar';
+}
diff --git a/src/Unit/Pressure/ExaPascal.php b/src/Unit/Pressure/ExaPascal.php
new file mode 100644
index 0000000..55f1e1a
--- /dev/null
+++ b/src/Unit/Pressure/ExaPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class ExaPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E18;
+
+    const SYMBOL = 'EPa';
+    const LABEL = 'exapascal';
+}
diff --git a/src/Unit/Pressure/FemtoBar.php b/src/Unit/Pressure/FemtoBar.php
new file mode 100644
index 0000000..d656d23
--- /dev/null
+++ b/src/Unit/Pressure/FemtoBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class FemtoBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E-15;
+
+    const SYMBOL = 'fbar';
+    const LABEL = 'femtobar';
+}
diff --git a/src/Unit/Pressure/FemtoPascal.php b/src/Unit/Pressure/FemtoPascal.php
new file mode 100644
index 0000000..f6a8593
--- /dev/null
+++ b/src/Unit/Pressure/FemtoPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class FemtoPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E-15;
+
+    const SYMBOL = 'fPa';
+    const LABEL = 'femtopascal';
+}
diff --git a/src/Unit/Pressure/FootOfMercury.php b/src/Unit/Pressure/FootOfMercury.php
new file mode 100644
index 0000000..047ad30
--- /dev/null
+++ b/src/Unit/Pressure/FootOfMercury.php
@@ -0,0 +1,10 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+class FootOfMercury extends InchOfMercury
+{
+	const FACTOR = 40636.664;
+
+    const SYMBOL = 'ftHg';
+    const LABEL = 'foot of mercury';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/FootOfWater.php b/src/Unit/Pressure/FootOfWater.php
new file mode 100644
index 0000000..f833d70
--- /dev/null
+++ b/src/Unit/Pressure/FootOfWater.php
@@ -0,0 +1,10 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+class FootOfWater extends InchOfWater
+{
+	const FACTOR = 2989.066899999973;
+
+    const SYMBOL = 'ftH2O';
+    const LABEL = 'foot of water';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/GigaBar.php b/src/Unit/Pressure/GigaBar.php
new file mode 100644
index 0000000..66f78bb
--- /dev/null
+++ b/src/Unit/Pressure/GigaBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class GigaBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E9;
+
+    const SYMBOL = 'Gbar';
+    const LABEL = 'gigabar';
+}
diff --git a/src/Unit/Pressure/GigaPascal.php b/src/Unit/Pressure/GigaPascal.php
new file mode 100644
index 0000000..83302b4
--- /dev/null
+++ b/src/Unit/Pressure/GigaPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class GigaPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E9;
+
+    const SYMBOL = 'GPa';
+    const LABEL = 'gigapascal';
+}
diff --git a/src/Unit/Pressure/HectoBar.php b/src/Unit/Pressure/HectoBar.php
new file mode 100644
index 0000000..f0cd65c
--- /dev/null
+++ b/src/Unit/Pressure/HectoBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class HectoBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E2;
+
+    const SYMBOL = 'hbar';
+    const LABEL = 'hectobar';
+}
diff --git a/src/Unit/Pressure/HectoPascal.php b/src/Unit/Pressure/HectoPascal.php
new file mode 100644
index 0000000..6cf71d0
--- /dev/null
+++ b/src/Unit/Pressure/HectoPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class HectoPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E2;
+
+    const SYMBOL = 'hPa';
+    const LABEL = 'hectopascal';
+}
diff --git a/src/Unit/Pressure/InchOfMercury.php b/src/Unit/Pressure/InchOfMercury.php
new file mode 100644
index 0000000..5184e0f
--- /dev/null
+++ b/src/Unit/Pressure/InchOfMercury.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\Unit\Pressure;
+
+class InchOfMercury extends Pressure
+{
+	const FACTOR = 3386.3886666666713;
+
+    const SYMBOL = 'inHg';
+    const LABEL = 'inch of mercury';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/InchOfWater.php b/src/Unit/Pressure/InchOfWater.php
new file mode 100644
index 0000000..2c5b72a
--- /dev/null
+++ b/src/Unit/Pressure/InchOfWater.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\Unit\Pressure;
+
+class InchOfWater extends Pressure
+{
+	const FACTOR = 249.0889083333348;
+
+    const SYMBOL = 'inH2O';
+    const LABEL = 'inch of water';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/KiloBar.php b/src/Unit/Pressure/KiloBar.php
new file mode 100644
index 0000000..a1611eb
--- /dev/null
+++ b/src/Unit/Pressure/KiloBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class KiloBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E3;
+
+    const SYMBOL = 'kbar';
+    const LABEL = 'kilobar';
+}
diff --git a/src/Unit/Pressure/KiloGramForcePerSquareMilliMetre.php b/src/Unit/Pressure/KiloGramForcePerSquareMilliMetre.php
new file mode 100644
index 0000000..5131517
--- /dev/null
+++ b/src/Unit/Pressure/KiloGramForcePerSquareMilliMetre.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\Unit\Pressure;
+
+class KiloGramForcePerSquareMilliMetre extends Pressure
+{
+	const FACTOR = 9806650;
+
+    const SYMBOL = 'kgf mm2';
+    const LABEL = 'kilogram-force per square millimetre';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/KiloPascal.php b/src/Unit/Pressure/KiloPascal.php
new file mode 100644
index 0000000..bd8849a
--- /dev/null
+++ b/src/Unit/Pressure/KiloPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class KiloPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E3;
+
+    const SYMBOL = 'kPa';
+    const LABEL = 'kilopascal';
+}
diff --git a/src/Unit/Pressure/KipPerSquareInch.php b/src/Unit/Pressure/KipPerSquareInch.php
new file mode 100644
index 0000000..4279f07
--- /dev/null
+++ b/src/Unit/Pressure/KipPerSquareInch.php
@@ -0,0 +1,13 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\USC;
+use PhpUnitConversion\Unit\Pressure;
+
+class KipPerSquareInch extends Pressure implements USC
+{
+	const FACTOR = 6894757.279999912;
+
+    const SYMBOL = 'ksi';
+    const LABEL = 'kip per square inch';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/MegaBar.php b/src/Unit/Pressure/MegaBar.php
new file mode 100644
index 0000000..843404d
--- /dev/null
+++ b/src/Unit/Pressure/MegaBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class MegaBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E6;
+
+    const SYMBOL = 'Mbar';
+    const LABEL = 'megabar';
+}
diff --git a/src/Unit/Pressure/MegaPascal.php b/src/Unit/Pressure/MegaPascal.php
new file mode 100644
index 0000000..54a715f
--- /dev/null
+++ b/src/Unit/Pressure/MegaPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class MegaPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E6;
+
+    const SYMBOL = 'MPa';
+    const LABEL = 'megapascal';
+}
diff --git a/src/Unit/Pressure/MicroBar.php b/src/Unit/Pressure/MicroBar.php
new file mode 100644
index 0000000..b28588d
--- /dev/null
+++ b/src/Unit/Pressure/MicroBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class MicroBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E-6;
+
+    const SYMBOL = 'μbar';
+    const LABEL = 'microbar';
+}
diff --git a/src/Unit/Pressure/MicroPascal.php b/src/Unit/Pressure/MicroPascal.php
new file mode 100644
index 0000000..9e9269e
--- /dev/null
+++ b/src/Unit/Pressure/MicroPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class MicroPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E-6;
+
+    const SYMBOL = 'μPa';
+    const LABEL = 'micropascal';
+}
diff --git a/src/Unit/Pressure/MilliBar.php b/src/Unit/Pressure/MilliBar.php
new file mode 100644
index 0000000..bc4c1fa
--- /dev/null
+++ b/src/Unit/Pressure/MilliBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class MilliBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E-3;
+
+    const SYMBOL = 'mbar';
+    const LABEL = 'millibar';
+}
diff --git a/src/Unit/Pressure/MilliMetreOfMercury.php b/src/Unit/Pressure/MilliMetreOfMercury.php
new file mode 100644
index 0000000..59f5c86
--- /dev/null
+++ b/src/Unit/Pressure/MilliMetreOfMercury.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\Unit\Pressure;
+
+class MilliMetreOfMercury extends Pressure
+{
+	const FACTOR = 133.322387415;
+
+    const SYMBOL = 'mmHg';
+    const LABEL = 'millimetre of mercury';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/MilliMetreOfWater.php b/src/Unit/Pressure/MilliMetreOfWater.php
new file mode 100644
index 0000000..c3ffbe5
--- /dev/null
+++ b/src/Unit/Pressure/MilliMetreOfWater.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\Unit\Pressure;
+
+class MilliMetreOfWater extends Pressure
+{
+	const FACTOR = 9.80638;
+
+    const SYMBOL = 'mmH2O';
+    const LABEL = 'millimetre of water';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/MilliPascal.php b/src/Unit/Pressure/MilliPascal.php
new file mode 100644
index 0000000..08c8643
--- /dev/null
+++ b/src/Unit/Pressure/MilliPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class MilliPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E-3;
+
+    const SYMBOL = 'mPa';
+    const LABEL = 'millipascal';
+}
diff --git a/src/Unit/Pressure/NanoBar.php b/src/Unit/Pressure/NanoBar.php
new file mode 100644
index 0000000..2731638
--- /dev/null
+++ b/src/Unit/Pressure/NanoBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class NanoBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E-9;
+
+    const SYMBOL = 'nbar';
+    const LABEL = 'nanobar';
+}
diff --git a/src/Unit/Pressure/NanoPascal.php b/src/Unit/Pressure/NanoPascal.php
new file mode 100644
index 0000000..4e1f6d2
--- /dev/null
+++ b/src/Unit/Pressure/NanoPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class NanoPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E-9;
+
+    const SYMBOL = 'nPa';
+    const LABEL = 'nanopascal';
+}
diff --git a/src/Unit/Pressure/Pascal.php b/src/Unit/Pressure/Pascal.php
new file mode 100644
index 0000000..44b480f
--- /dev/null
+++ b/src/Unit/Pressure/Pascal.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\BaseUnit;
+use PhpUnitConversion\Unit\Pressure;
+
+class Pascal extends Pressure implements Metric
+{
+	use BaseUnit;
+
+    const SYMBOL = 'Pa';
+    const LABEL = 'pascal';
+}
diff --git a/src/Unit/Pressure/PetaBar.php b/src/Unit/Pressure/PetaBar.php
new file mode 100644
index 0000000..01ad47f
--- /dev/null
+++ b/src/Unit/Pressure/PetaBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class PetaBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E15;
+
+    const SYMBOL = 'Pbar';
+    const LABEL = 'petabar';
+}
diff --git a/src/Unit/Pressure/PetaPascal.php b/src/Unit/Pressure/PetaPascal.php
new file mode 100644
index 0000000..2077d86
--- /dev/null
+++ b/src/Unit/Pressure/PetaPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class PetaPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E15;
+
+    const SYMBOL = 'PPa';
+    const LABEL = 'petapascal';
+}
diff --git a/src/Unit/Pressure/PicoBar.php b/src/Unit/Pressure/PicoBar.php
new file mode 100644
index 0000000..acd3152
--- /dev/null
+++ b/src/Unit/Pressure/PicoBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class PicoBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E-12;
+
+    const SYMBOL = 'pbar';
+    const LABEL = 'picobar';
+}
diff --git a/src/Unit/Pressure/PicoPascal.php b/src/Unit/Pressure/PicoPascal.php
new file mode 100644
index 0000000..6b4713a
--- /dev/null
+++ b/src/Unit/Pressure/PicoPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class PicoPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E-12;
+
+    const SYMBOL = 'pPa';
+    const LABEL = 'picopascal';
+}
diff --git a/src/Unit/Pressure/Pieze.php b/src/Unit/Pressure/Pieze.php
new file mode 100644
index 0000000..a3244bd
--- /dev/null
+++ b/src/Unit/Pressure/Pieze.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\Unit\Pressure;
+
+class Pieze extends Pressure
+{
+	const FACTOR = 1E3;
+
+    const SYMBOL = 'pz';
+    const LABEL = 'pièze';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/PoundPerSquareFoot.php b/src/Unit/Pressure/PoundPerSquareFoot.php
new file mode 100644
index 0000000..66c1950
--- /dev/null
+++ b/src/Unit/Pressure/PoundPerSquareFoot.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\USC;
+
+class PoundPerSquareFoot extends PoundPerSquareInch implements USC
+{
+	const FACTOR = 47.88025;
+
+    const SYMBOL = 'psf';
+    const LABEL = 'pound per square foot';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/PoundPerSquareInch.php b/src/Unit/Pressure/PoundPerSquareInch.php
new file mode 100644
index 0000000..e7aa708
--- /dev/null
+++ b/src/Unit/Pressure/PoundPerSquareInch.php
@@ -0,0 +1,13 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\USC;
+use PhpUnitConversion\Unit\Pressure;
+
+class PoundPerSquareInch extends Pressure implements USC
+{
+	const FACTOR = 6894.75728;
+
+    const SYMBOL = 'psi';
+    const LABEL = 'pound per square inch';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/PoundalPerSquareFoot.php b/src/Unit/Pressure/PoundalPerSquareFoot.php
new file mode 100644
index 0000000..61f6363
--- /dev/null
+++ b/src/Unit/Pressure/PoundalPerSquareFoot.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\Unit\Pressure;
+
+class PoundalPerSquareFoot extends Pressure
+{
+	const FACTOR = 1.4881638964666748;
+
+    const SYMBOL = 'pdl/sq ft';
+    const LABEL = 'poundal per square foot';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/StandardAtmosphere.php b/src/Unit/Pressure/StandardAtmosphere.php
new file mode 100644
index 0000000..8d51c74
--- /dev/null
+++ b/src/Unit/Pressure/StandardAtmosphere.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\Unit\Pressure;
+
+class StandardAtmosphere extends Pressure
+{
+	const FACTOR = 101325;
+
+    const SYMBOL = 'atm';
+    const LABEL = 'standard atmosphere';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/TechnicalAtmosphere.php b/src/Unit/Pressure/TechnicalAtmosphere.php
new file mode 100644
index 0000000..82b4686
--- /dev/null
+++ b/src/Unit/Pressure/TechnicalAtmosphere.php
@@ -0,0 +1,10 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+class TechnicalAtmosphere extends StandardAtmosphere
+{
+	const FACTOR = 98066.5;
+
+    const SYMBOL = 'at';
+    const LABEL = 'technical atmosphere';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/TeraBar.php b/src/Unit/Pressure/TeraBar.php
new file mode 100644
index 0000000..7b5dae0
--- /dev/null
+++ b/src/Unit/Pressure/TeraBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class TeraBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E12;
+
+    const SYMBOL = 'Tbar';
+    const LABEL = 'terabar';
+}
diff --git a/src/Unit/Pressure/TeraPascal.php b/src/Unit/Pressure/TeraPascal.php
new file mode 100644
index 0000000..7deb758
--- /dev/null
+++ b/src/Unit/Pressure/TeraPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class TeraPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E12;
+
+    const SYMBOL = 'TPa';
+    const LABEL = 'terapascal';
+}
diff --git a/src/Unit/Pressure/Torr.php b/src/Unit/Pressure/Torr.php
new file mode 100644
index 0000000..7a34fae
--- /dev/null
+++ b/src/Unit/Pressure/Torr.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\Unit\Pressure;
+
+class Torr extends Pressure
+{
+	const FACTOR = 133.3224;
+
+    const SYMBOL = 'Torr';
+    const LABEL = 'torr';
+}
\ No newline at end of file
diff --git a/src/Unit/Pressure/YoctoBar.php b/src/Unit/Pressure/YoctoBar.php
new file mode 100644
index 0000000..e8f9d98
--- /dev/null
+++ b/src/Unit/Pressure/YoctoBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class YoctoBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E-24;
+
+    const SYMBOL = 'ybar';
+    const LABEL = 'yoctobar';
+}
diff --git a/src/Unit/Pressure/YoctoPascal.php b/src/Unit/Pressure/YoctoPascal.php
new file mode 100644
index 0000000..046024c
--- /dev/null
+++ b/src/Unit/Pressure/YoctoPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class YoctoPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E-24;
+
+    const SYMBOL = 'yPa';
+    const LABEL = 'yoctopascal';
+}
diff --git a/src/Unit/Pressure/YottaBar.php b/src/Unit/Pressure/YottaBar.php
new file mode 100644
index 0000000..dcfa871
--- /dev/null
+++ b/src/Unit/Pressure/YottaBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class YottaBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E24;
+
+    const SYMBOL = 'Ybar';
+    const LABEL = 'yottabar';
+}
diff --git a/src/Unit/Pressure/YottaPascal.php b/src/Unit/Pressure/YottaPascal.php
new file mode 100644
index 0000000..259671b
--- /dev/null
+++ b/src/Unit/Pressure/YottaPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class YottaPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E24;
+
+    const SYMBOL = 'YPa';
+    const LABEL = 'yottapascal';
+}
diff --git a/src/Unit/Pressure/ZeptoBar.php b/src/Unit/Pressure/ZeptoBar.php
new file mode 100644
index 0000000..3548b9c
--- /dev/null
+++ b/src/Unit/Pressure/ZeptoBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class ZeptoBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E-21;
+
+    const SYMBOL = 'zbar';
+    const LABEL = 'zeptobar';
+}
diff --git a/src/Unit/Pressure/ZeptoPascal.php b/src/Unit/Pressure/ZeptoPascal.php
new file mode 100644
index 0000000..be2e8a9
--- /dev/null
+++ b/src/Unit/Pressure/ZeptoPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class ZeptoPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E-21;
+
+    const SYMBOL = 'zPa';
+    const LABEL = 'zeptopascal';
+}
diff --git a/src/Unit/Pressure/ZettaBar.php b/src/Unit/Pressure/ZettaBar.php
new file mode 100644
index 0000000..f8f71a5
--- /dev/null
+++ b/src/Unit/Pressure/ZettaBar.php
@@ -0,0 +1,15 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+use PhpUnitConversion\Traits\HasRelativeFactor;
+
+class ZettaBar extends Bar implements Metric
+{
+    use HasRelativeFactor;
+
+    const FACTOR = 1E21;
+
+    const SYMBOL = 'Zbar';
+    const LABEL = 'zettabar';
+}
diff --git a/src/Unit/Pressure/ZettaPascal.php b/src/Unit/Pressure/ZettaPascal.php
new file mode 100644
index 0000000..8421c7e
--- /dev/null
+++ b/src/Unit/Pressure/ZettaPascal.php
@@ -0,0 +1,12 @@
+<?php
+namespace PhpUnitConversion\Unit\Pressure;
+
+use PhpUnitConversion\System\Metric;
+
+class ZettaPascal extends Pascal implements Metric
+{
+    const FACTOR = 1E21;
+
+    const SYMBOL = 'ZPa';
+    const LABEL = 'zettapascal';
+}
diff --git a/src/UnitType.php b/src/UnitType.php
index 2f365a7..6f59c10 100644
--- a/src/UnitType.php
+++ b/src/UnitType.php
@@ -15,4 +15,5 @@ class UnitType extends Enum
     const TEMPERATURE = 6;
     const AMOUNT = 7;
     const VELOCITY = 8;
+    const PRESSURE = 9;
 }
diff --git a/tests/Unit/PressureTest.php b/tests/Unit/PressureTest.php
new file mode 100644
index 0000000..0803b29
--- /dev/null
+++ b/tests/Unit/PressureTest.php
@@ -0,0 +1,188 @@
+<?php
+namespace PhpUnitConversionTest\Unit;
+
+use PHPUnit\Framework\TestCase;
+use PhpUnitConversion\Exception;
+use PhpUnitConversion\Unit;
+use PhpUnitConversion\Unit\Pressure;
+
+class PressureTest extends TestCase
+{
+    public function testFromBar()
+    {
+        $pressUnit = new Pressure\Bar(1);
+        $this->assertEquals('100000.00 Pa', Pressure\Pascal::from($pressUnit)->format(2));
+    }
+
+    public function testFromBarye()
+    {
+        $pressUnit = new Pressure\Barye(10);
+        $this->assertEquals('1.00 Pa', Pressure\Pascal::from($pressUnit)->format(2));
+    }
+
+    public function testFromMilliMetreOfMercury()
+    {
+        $pressUnit = new Pressure\MilliMetreOfMercury(1);
+        $this->assertEquals('133.3224 Pa', Pressure\Pascal::from($pressUnit)->format(4));
+    }
+
+    public function testFromCentiMetreOfMercury()
+    {
+        $pressUnit = new Pressure\CentiMetreOfMercury(1);
+        $this->assertEquals('1333.2239 Pa', Pressure\Pascal::from($pressUnit)->format(4));
+    }
+
+    public function testFromInchOfMercury()
+    {
+        $pressUnit = new Pressure\InchOfMercury(0.5);
+        $this->assertEquals('1693.1943 Pa', Pressure\Pascal::from($pressUnit)->format(4));
+    }
+
+    public function testFromFootOfMercury()
+    {
+        $pressUnit = new Pressure\FootOfMercury(2);
+        $this->assertEquals('81273.3280 Pa', Pressure\Pascal::from($pressUnit)->format(4));
+    }
+
+    public function testFromMilliMetreOfWater()
+    {
+        $pressUnit = new Pressure\MilliMetreOfWater(12);
+        $this->assertEquals('117.6766 Pa', Pressure\Pascal::from($pressUnit)->format(4));
+    }
+
+    public function testFromCentiMetreOfWater()
+    {
+        $pressUnit = new Pressure\CentiMetreOfWater(12);
+        $this->assertEquals('1176.7656 Pa', Pressure\Pascal::from($pressUnit)->format(4));
+    }
+
+    public function testFromInchOfWater()
+    {
+        $pressUnit = new Pressure\InchOfWater(0.01);
+        $this->assertEquals('2.4909 Pa', Pressure\Pascal::from($pressUnit)->format(4));
+    }
+
+    public function testFromFootOfWater()
+    {
+        $pressUnit = new Pressure\FootOfWater(5);
+        $this->assertEquals('14945.3345 Pa', Pressure\Pascal::from($pressUnit)->format(4));
+    }
+
+    public function testFromPoundPerSquareInch()
+    {
+        $pressUnit = new Pressure\PoundPerSquareInch(1);
+        $this->assertEquals('6894.7573 Pa', Pressure\Pascal::from($pressUnit)->format(4));
+    }
+
+    public function testFromPoundPerSquareFoot()
+    {
+        $pressUnit = new Pressure\PoundPerSquareFoot(4);
+        $this->assertEquals('191.5210 Pa', Pressure\Pascal::from($pressUnit)->format(4));
+    }
+
+    public function testFromPoundalPerSquareFoot()
+    {
+        $pressUnit = new Pressure\PoundalPerSquareFoot(7);
+        $this->assertEquals('10.4171 Pa', Pressure\Pascal::from($pressUnit)->format(4));
+    }
+
+    public function testFromKiloGramForcePerSquareMilliMetre()
+    {
+        $pressUnit = new Pressure\KiloGramForcePerSquareMilliMetre(0.5);
+        $this->assertEquals('4903325 Pa', Pressure\Pascal::from($pressUnit)->format(0));
+    }
+
+    public function testFromKipPerSquareInch()
+    {
+        $pressUnit = new Pressure\KipPerSquareInch(0.95);
+        $this->assertEquals('6550019.4160 Pa', Pressure\Pascal::from($pressUnit)->format(4));
+    }
+
+    public function testFromStandardAtmosphere()
+    {
+        $pressUnit = new Pressure\StandardAtmosphere(1);
+        $this->assertEquals('101325.00 Pa', Pressure\Pascal::from($pressUnit)->format(2));
+    }
+
+    public function testFromTechnicalAtmosphere()
+    {
+        $pressUnit = new Pressure\TechnicalAtmosphere(1);
+        $this->assertEquals('98066 Pa', Pressure\Pascal::from($pressUnit)->format(0));
+    }
+
+    public function testFromPieze()
+    {
+        $pressUnit = new Pressure\Pieze(3.13);
+        $this->assertEquals('3130 Pa', Pressure\Pascal::from($pressUnit)->format(0));
+    }
+
+    public function testFromTorr()
+    {
+        $pressUnit = new Pressure\Torr(1);
+        $this->assertEquals('133.3224 Pa', Pressure\Pascal::from($pressUnit)->format(4));
+    }
+
+    public function testToMilliPascal()
+    {
+        $pressUnit = new Pressure\Pascal(21);
+
+        $milliPascal = $pressUnit->to(Pressure\MilliPascal::class);
+
+        $this->assertEquals('21000 mPa', $milliPascal->format(0));
+    }
+
+    public function testToKiloPascal()
+    {
+        $pressUnit = new Pressure\Pascal(21);
+        $kiloPascal = new Pressure\KiloPascal;
+
+        $pressUnit->to($kiloPascal);
+
+        $this->assertEquals('0.021 kPa', $kiloPascal->format());
+    }
+
+    public function testToBar()
+    {
+        $pressUnit = new Pressure\Pascal(1E5);
+
+        $bar = $pressUnit->to(new Pressure\Bar);
+
+        $this->assertEquals('1.00 bar', $bar->format(2));
+    }
+
+    public function testToTimeWhichShouldFail()
+    {
+        $this->expectException(Exception::class);
+
+        $pressUnit = new Pressure\Pascal(1);
+
+        $ounce = $pressUnit->to(new Unit\Time\Second);
+    }
+
+    public function testFromString()
+    {
+        $pressUnit = Unit::from('5 kPa');
+
+        $this->assertInstanceOf(Pressure\KiloPascal::class, $pressUnit);
+    }
+
+    public function testAddition()
+    {
+        $pressUnit = new Pressure\Pascal(321);
+
+        $newUnit = $pressUnit->add(new Pressure\Bar(0.1), new Pressure\Pascal(123));
+
+        $this->assertEquals('10444 Pa', $newUnit->format(0));
+    }
+
+    public function testSubstraction()
+    {
+        $pressUnit = new Pressure\Pascal(10444);
+
+        $newUnit = $pressUnit->substract(
+            new Pressure\MilliMetreOfMercury(1), new Pressure\Pascal(123)
+        );
+
+        $this->assertEquals('10187.6776 Pa', $newUnit->format(4));
+    }
+}