Pressure Converter

This page converts a pressure from one unit into another. Every value passes through the pascal, the SI unit pressure is held in, and pressure stays pressure: a unit only converts inside its own dimension.

How do you convert pressure between bar, psi, pascals and atmospheres?

Pick the unit you have, pick the unit you want, and type the value. The page multiplies by the factor between the two and prints the arithmetic under the result, so the answer and the working are the same object.

1. Choose the unit your value is in. This page opens on the standard atmosphere.
2. Choose the unit you want it in. This page opens on the pound-force per square inch.
3. Type the value. The result and the factor behind it appear together.
4. Read the working. It converts into the pascal first and out again, which is the same two lines you would write by hand.

Pressure Conversion Table

One row per unit this page offers, each measured against the pascal. The last column says whether the factor is a definition or a reading of one.

Worked Examples

The question the bank ranked highest for this page, answered with the working.

Where These Factors Come From

Every number above is read from the knowledge base rather than computed for the page. These are the statements it holds for pressure.

• One pascal is one newton per square metre. One bar is exactly 100 000 Pa and one standard atmosphere is exactly 101 325 Pa, so a bar and an atmosphere are close but not the same.
• One pound-force per square inch is 4.4482216152605 N spread over 0.00064516 m2, which is 6894.757293168361 Pa. One conventional millimetre of mercury is exactly 133.322387415 Pa.
• An exact factor is a definition rather than a measurement. 1 in = 25.4 mm and 1 lb = 0.45359237 kg were fixed by the 1959 international yard and pound agreement, so they never gain another digit.
• standard acceleration of free fall, value 9.80665
• How this page reports a result result in the target pressure unit; gauge and absolute are not converted between

SI prefixes on this page

Gauge or Absolute Pressure?

Gauge pressure is measured against the surrounding air and absolute pressure against a vacuum. This page converts pressure units; it does not convert between the two references, so a gauge reading stays a gauge reading and an absolute reading stays absolute.

The rule behind this factor is the same for every unit - cancelling the unit you are leaving.

Frequently Asked Questions

Related Conversions

• Mass sits in the same measurement group as pressure - convert a mass between kilograms and pounds.
• Torque sits in the same measurement group as pressure - convert torque between newton-metres and pound-feet.
• Pace sits in the same measurement group as pressure - convert a running pace between minutes per kilometre and minutes per mile.
• Speed sits in the same measurement group as pressure - speed in metres per second, km/h, mph and knots.
• If you are measuring volumetric flow rate rather than pressure, flow rate in litres per minute, cubic metres per hour and gallons per minute instead.
• If you are measuring power rather than pressure, the watt-based factor table instead.

The rest of the family sits on the rest of the measurement families.