Pressure Conversion Calculator

Pressure describes force distributed over an area, but the same pressure can be written in many units. This page starts with bar and shows the equivalent value in standard atmospheres, pascals and pounds-force per square inch (psi). It is useful when a gauge, specification sheet or technical note uses a different unit from the one you need.

The conversion changes the numerical scale, not the physical pressure. It also does not change the pressure reference. A gauge pressure is measured relative to local atmospheric pressure, while absolute pressure is measured from a vacuum. Converting a gauge value to psi still gives gauge pressure unless an atmospheric offset is separately added under appropriate conditions.

1. Read the source value carefully and confirm that it is expressed in bar.
2. Enter the signed decimal value. Positive values are common, but a negative gauge pressure can describe a partial vacuum relative to the local atmosphere.
3. Select Calculate. The page converts bar to pascals, then converts pascals to standard atmospheres and psi using their defined pressure values.
4. Read atmosphere, pascal and psi outputs. The page rounds them to six, two and four decimal places respectively.
5. Carry the original pressure type—absolute, gauge or differential—alongside the converted number so the result is not mistaken for another reference basis.

No temperature or altitude adjustment occurs. Unit conversion factors are fixed; a change between gauge and absolute pressure is a separate operation involving the applicable atmospheric pressure.

Use the destination value that matches the specification or instrument you are comparing against. A result near 0.986923 atm for 1 bar is expected because one standard atmosphere is slightly larger than one bar. A result of 100,000 Pa for 1 bar is exact by definition.

Conversion alone cannot tell whether equipment is operating safely. Pressure limits may specify absolute pressure, gauge pressure, proof pressure, working pressure or a temperature-dependent rating. Check the equipment documentation and preserve its units and reference. The page also does not account for uncertainty or calibrate a sensor; it only applies arithmetic factors to the entered number.