PSI to Bar Converter
To convert PSI to bar, multiply by 0.0689475729316836. This factor is derived from the exact definitions: 1 psi = 6894.757293168 pascals and 1 bar = 100,000 pascals.
Formula
bar = psi × 0.0689475729316836
Reverse (bar to psi):
psi = bar × 14.503773773020924
Formula variables
- psi — pressure in pounds per square inch.
- bar — equivalent pressure in bar.
- 0.0689475729316836 — the ratio 6894.757293168 / 100,000, where 1 psi = 6894.757293168 Pa and 1 bar = 100,000 Pa exactly.
Worked Examples
Example 1: 1 psi to bar
- Start: 1 psi.
- Multiply: 1 × 0.0689475729316836 = 0.0689475729316836.
- Result: 1 psi ≈ 0.068948 bar.
Example 2: 32 psi to bar (typical US car tire)
- Start: 32 psi.
- Multiply: 32 × 0.0689475729316836 = 2.206322333813875.
- Result: 32 psi ≈ 2.2063 bar. A typical US passenger car tire pressure.
Example 3: 100 psi to bar
- Start: 100 psi.
- Multiply: 100 × 0.0689475729316836 = 6.89475729316836.
- Result: 100 psi ≈ 6.895 bar. A common value in hydraulic and pneumatic systems.
Common Conversion Table
| PSI | Bar |
|---|---|
| 1 | 0.0689 |
| 5 | 0.3447 |
| 10 | 0.6895 |
| 14.504 | 1.000 |
| 15 | 1.0342 |
| 20 | 1.3790 |
| 30 | 2.0684 |
| 32 | 2.2063 |
| 35 | 2.4132 |
| 40 | 2.7579 |
| 50 | 3.4474 |
| 100 | 6.8948 |
| 150 | 10.3421 |
| 200 | 13.7895 |
Tire Pressure Reference (psi to bar)
| Application | psi | bar |
|---|---|---|
| Passenger car (low) | 30 | 2.07 |
| Passenger car (typical) | 32 | 2.21 |
| Passenger car (high) | 35 | 2.41 |
| SUV / light truck | 40 | 2.76 |
| Compact spare | 60 | 4.14 |
| Bicycle road tire | 100 | 6.89 |
| Bicycle mountain tire | 30 | 2.07 |
| Heavy truck tire | 110 | 7.58 |
Real-World Uses
- Automotive tire pressure: The US uses psi; Europe uses bar. Knowing both allows quick reading of vehicle manuals from either region.
- Hydraulics and pneumatics: Industrial equipment in the US uses psi; European equipment often uses bar.
- Scuba diving: Cylinder pressures may be quoted in either psi or bar depending on the region.
- Weather and meteorology: Atmospheric pressure is usually in hPa/mbar (which are numerically equal to 100 Pa), but conversation often involves psi in aviation contexts.
Unit Definitions
PSI (Pound per Square Inch)
A customary and imperial unit of pressure equal to one pound-force per square inch. It derives from exact definitions: 1 lb = 0.45359237 kg and g₀ = 9.80665 m/s², giving 1 psi = 6894.757293168 pascals.
Bar
A metric unit of pressure equal to exactly 100,000 pascals. It is not an SI unit but is accepted for use with SI. Bar was chosen so that atmospheric pressure at sea level is very close to 1 bar (about 1.013 bar).
Accuracy and Rounding
The conversion factor between psi and bar is exact to the precision of the psi definition, which itself is exact given the exact pound and standard-gravity definitions. In practice, tire pressure gauges and equipment are accurate to a few percent, so displayed conversions often round to 2 decimal places.
Related Converters
- Bar to PSI — reverse conversion
- kPa to PSI
- PSI to kPa
- mmHg to kPa
- All Pressure Converters
Frequently Asked Questions
How do you convert psi to bar?
Multiply the psi value by 0.0689475729316836. For example, 32 psi × 0.0689475729316836 ≈ 2.2063 bar.
What is 32 psi in bar?
32 psi ≈ 2.2063 bar. This is a common passenger car tire pressure in the US and roughly matches the European standard of 2.2 bar.
What is 1 bar in psi?
1 bar = 14.503773773020924 psi approximately, or 14.504 psi for practical purposes.
What is 2.5 bar in psi?
2.5 bar ≈ 36.259 psi. This is the high end of common passenger car tire pressures in Europe.
Is 1 bar the same as 1 atmosphere?
No. 1 bar = 100,000 Pa exactly, while 1 atm = 101,325 Pa exactly. They differ by about 1.3%.