About the Pressure Converter
This pressure converter handles every unit you are likely to meet: psi for tyres and compressors, bar and kPa on European gauges, MPa in engineering specs, atmospheres in chemistry, mmHg and torr for blood pressure and vacuum work, inches of mercury in weather reports and aviation, inches of water for HVAC duct pressure, and kgf/cm² on older equipment.
Enter a number, choose the unit it is in and the unit you want, and the headline answer appears with the full table of equivalents underneath. It is designed for mechanics, cyclists, divers, HVAC technicians, students and anyone reading a gauge marked in a different system.
All factors come from the official definitions (1 psi = 6894.757 Pa, 1 bar = 100,000 Pa, 1 atm = 101,325 Pa). The tool converts the number you enter as-is, so gauge pressure stays gauge pressure — add about 14.7 psi (1.013 bar) if you need absolute pressure at sea level.
How to use the pressure converter
- 1Type the pressure reading you want to convert.
- 2Select the unit it is in (for example psi).
- 3Select the unit you need (for example bar or kPa).
- 4Read the result and check the table for every other unit.
Formula and method
Each unit is defined by how many pascals (newtons per square metre) it contains. The converter multiplies your value by the pascals in the source unit, then divides by the pascals in the target unit. 1 psi is one pound-force on a square inch, 4.4482216 N ÷ 0.00064516 m² = 6894.757 Pa; 1 bar is exactly 100,000 Pa; 1 atm is exactly 101,325 Pa.
Mercury and water column units use the conventional values listed by NIST, which assume standard gravity (9.80665 m/s²) and fixed densities of 13,595.1 kg/m³ for mercury and 1,000 kg/m³ for water: 1 mmHg = 133.322 Pa, 1 inHg = 3386.389 Pa and 1 inH₂O = 249.089 Pa. Readings taken at a specific temperature (for example inH₂O at 39.2 °F = 249.082 Pa, or at 60 °F) differ very slightly. One torr is defined as 1/760 of an atmosphere, which is within 0.000015% of 1 mmHg.
- Pa
- Pascal, one newton per square metre (SI unit)
- psi
- Pound-force per square inch = 6894.757 Pa
- bar
- 100,000 Pa (100 kPa)
- atm
- Standard atmosphere = 101,325 Pa
Worked examples
One standard atmosphere
101,325 Pa ÷ 6894.757 Pa per psi = 14.696 psi. The same pressure is 101.325 kPa and, by definition of the mmHg, about 760 mmHg.
2.5 bar tyre pressure in psi
2.5 bar is 250,000 Pa. Dividing by 6894.757 gives 36.26 psi — a common front-tyre setting on European cars.
Barometer reading of 29.92 inHg
29.92 × 3386.389 Pa = 101,320.8 Pa, which is 1013.2 mbar (hPa) — the standard altimeter setting used in aviation.
Frequently asked questions
How do I convert psi to bar?+
Divide psi by 14.5038 (or multiply by 0.0689476). For example, 32 psi × 0.0689476 = 2.206 bar. To go from bar to psi, multiply by 14.5038.
How many kPa are in one psi?+
One psi equals 6.894757 kPa. So 35 psi is about 241.3 kPa, and 100 kPa is about 14.5 psi.
Is 1 bar the same as 1 atmosphere?+
Almost but not quite. 1 bar is 100,000 Pa and 1 atm is 101,325 Pa, so 1 atm = 1.01325 bar. The difference is about 1.3%.
What is the difference between psi and psig?+
psig is gauge pressure measured relative to the surrounding air, which is what tyre gauges show. psia is absolute pressure measured from a vacuum; at sea level psia ≈ psig + 14.7.
Are mmHg and torr the same?+
For practical purposes yes. A torr is exactly 1/760 atm (133.3224 Pa) and 1 mmHg is 133.3224 Pa; they differ by less than one part in a million.