How to Convert PSI to Bar
A complete guide to converting PSI (pounds per square inch) to bar, including the exact formula, worked examples, a reference table, and applications for tire pressure, hydraulics, and diving.
Last updated: 2025-03-13
The PSI to Bar Formula
PSI (pounds per square inch) and bar are both units of pressure. One PSI equals approximately 0.0689476 bar, and conversely, one bar equals approximately 14.5038 PSI. The formula is:
bar = PSI × 0.0689476
PSI is the standard pressure unit in the United States, used for tire pressure, water pressure, and industrial applications. The bar is widely used in Europe and in international engineering, meteorology, and diving. One bar is defined as exactly 100,000 pascals (100 kPa) and is approximately equal to atmospheric pressure at sea level (1 atm = 1.01325 bar).
Step-by-Step Examples
Example 1: Converting 32 PSI (Tire Pressure) to Bar
- Step 1: Take the pressure: 32 PSI.
- Step 2: Multiply by 0.0689476: 32 × 0.0689476 = 2.2063.
- Result: 32 PSI equals approximately 2.21 bar.
Example 2: Converting 100 PSI to Bar
- Step 1: Take the pressure: 100 PSI.
- Step 2: Multiply: 100 × 0.0689476 = 6.89476.
- Result: 100 PSI equals approximately 6.89 bar.
Example 3: Converting 3,000 PSI (SCUBA Tank) to Bar
- Step 1: Take the pressure: 3,000 PSI.
- Step 2: Multiply: 3,000 × 0.0689476 = 206.843.
- Result: 3,000 PSI equals approximately 206.8 bar.
Use our pressure converter for instant, precise results.
Quick Reference Table
| PSI | Bar | Common Use |
|---|---|---|
| 14.7 PSI | 1.013 bar | Atmospheric pressure |
| 30 PSI | 2.07 bar | Car tire (low end) |
| 35 PSI | 2.41 bar | Car tire (typical) |
| 40 PSI | 2.76 bar | Car tire (high end) |
| 80 PSI | 5.52 bar | Bicycle tire (road) |
| 120 PSI | 8.27 bar | Bicycle tire (high pressure) |
| 150 PSI | 10.34 bar | Air compressor |
| 3,000 PSI | 206.8 bar | SCUBA tank (aluminum) |
| 3,500 PSI | 241.3 bar | SCUBA tank (steel) |
The Reverse Formula: Bar to PSI
To convert bar to PSI, divide by 0.0689476 or multiply by 14.5038:
PSI = bar × 14.5038
For example, 2.5 bar × 14.5038 = 36.26 PSI. Our pressure converter handles both directions.
Quick Mental Math Trick
For a fast PSI-to-bar estimate, divide PSI by 14.5 (or roughly by 15 for even quicker math). So 45 PSI ÷ 15 = 3 bar (actual: 3.10 bar). Going the other way, multiply bar by 14.5: 2 bar × 14.5 = 29 PSI (actual: 29.01 PSI). The factor of ~14.5 is convenient because it is close to 15, making division simple.
Real-World Applications
Tire Pressure
US tire gauges read in PSI, while European gauges typically show bar. A placard on your car might say 35 PSI, which equals 2.41 bar. Many modern tire gauges display both units, but knowing the conversion helps when using equipment in a different country. Proper tire pressure improves fuel economy, handling, and tire life.
SCUBA Diving
US dive shops measure tank pressure in PSI, while the rest of the world uses bar. A full aluminum tank is typically 3,000 PSI (207 bar), and divers plan to surface with at least 500 PSI (34.5 bar) remaining. Dive computers may display in either unit, so conversion fluency is important for safety.
Industrial and Hydraulic Systems
Hydraulic systems operate at pressures from a few hundred to several thousand PSI. A typical hydraulic excavator operates at 3,000–5,000 PSI (207–345 bar). Equipment manufactured in different countries may have pressure ratings in either unit, requiring accurate conversion for maintenance and safety.
Weather and Meteorology
While meteorologists typically use hectopascals (hPa) or millibars (mbar), some weather stations report in bar. Standard atmospheric pressure is 1.01325 bar or 14.696 PSI. A barometric pressure reading helps predict weather patterns.
Frequently Asked Questions
How many bar is 1 PSI?
1 PSI equals approximately 0.0689476 bar. Multiply any PSI value by 0.0689476 to get bar.
How do I convert tire pressure from PSI to bar?
Multiply the PSI value by 0.0689476. Common results: 30 PSI = 2.07 bar, 32 PSI = 2.21 bar, 35 PSI = 2.41 bar, 40 PSI = 2.76 bar.
What is the relationship between bar and atmospheric pressure?
One bar (100,000 Pa) is approximately equal to one standard atmosphere (101,325 Pa). More precisely, 1 atm = 1.01325 bar = 14.696 PSI.
Quick Reference Section
- PSI to Bar: bar = PSI × 0.0689476
- Bar to PSI: PSI = bar × 14.5038
- Mental shortcut: Divide PSI by ~14.5 to estimate bar
- Key anchor: 14.7 PSI ≈ 1 bar ≈ 1 atmosphere
For precise conversions, use our free pressure converter.