Pounds per square inch to bar (psi to bar)

The formula

bar = psi × 0.06894757293

Where the factor comes from — each unit by its definition, then its size in SI:

• 1 psi = lbf / in² = 6,894.75729317 Pa
• 1 bar = 100 × kPa = 100,000 Pa

Dividing the two SI sizes gives the factor: 0.0689475729317 (rounded for display; the underlying ratio is fixed by the definitions). The reverse factor is 14.503773773.

Pressure is force per area; the pascal is one newton per square metre. Tyres are quoted in psi or bar, weather in hPa, blood pressure in mmHg and gas laws in pascals or atmospheres.

Worked examples

• A car tyre (US gauge): 32 psi = 2.20632 bar — 32 × 0.06894757293 = 2.20632
• Sea-level air (1 atm): 14.6959 psi = 1.01325 bar — 14.6959 × 0.06894757293 = 1.01325
• A car tyre (European gauge): 31.9083 psi = 2.2 bar — 31.9083 × 0.06894757293 = 2.2
• A systolic blood-pressure reading (120 mmHg): 2.32041 psi = 0.159987 bar — 2.32041 × 0.06894757293 = 0.159987

Frequently asked questions