The short answer: 100 pounds per square inch comes to 6.894757293 bar. That is 100 multiplied by 0.06894757293, the factor fixed by definition, carried to full precision before anything is rounded for display.
100 psi is 6.895 bar and 689.48 kPa. Passenger-car placards normally sit between 30 and 36 psi cold, road bicycle tyres between 80 and 110, and domestic mains water between 40 and 70 — so the same number means very different things depending on what is being inflated.
The result sits 0.1052 bar short of 7 bar, so if you need a round figure to quote, 7 bar is the honest nearest one. Plenty of people do this in their head: divide by 15 instead of using the exact factor 0.06894757293. At 100 that shortcut gives 6.6666667 bar, off by 0.2281 bar or about 3.31%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
The formula
100 psi- The quantity being converted
0.06894757293- Exact bar in one pound per square inch
6.894757293 bar- The converted result
How it works, step by step
- Begin from the figure you have: 100 pounds per square inch.
- Scale it by 0.06894757293 — that is how many bar fit in a single pound per square inch.
- The product is 6.89475729317 bar.
- The reverse works the same way with division: 6.894757293 bar ÷ 0.06894757293 = 100 psi.
Worked examples
Step by step
Take 100 psi and multiply by the factor 0.06894757293. The product is 6.89475729317 bar, and that is the entire method.
Proving it both ways
Run it in reverse — 6.894757293 bar ÷ 0.06894757293 = 100 psi. Matching the input you started from is the proof the direction is right.
How to read your score
Frequently asked questions
What is 100 pounds per square inch in bar?
100 pounds per square inch is exactly 6.894757293 bar. Carried to full precision that is 6.89475729317 bar.
How do you convert pounds per square inch to bar?
Multiply by 0.06894757293. So 100 × 0.06894757293 = 6.894757293 bar. The factor comes from a definition rather than a measurement, so it never changes.
What is 6.894757293 bar back in pounds per square inch?
It goes back to 100 pounds per square inch. The reciprocal of the factor is 14.50377377, so multiplying by that works just as well as dividing.
Is 100 psi a lot?
100 psi is 6.895 bar and 689.48 kPa. Passenger-car placards normally sit between 30 and 36 psi cold, road bicycle tyres between 80 and 110, and domestic mains water between 40 and 70 — so the same number means very different things depending on what is being inflated. Compare it against the surrounding values in the table below.
What is a pound per square inch?
The dominant US pressure unit for tyres, plumbing and compressors.
What is a bar?
Almost exactly atmospheric pressure; standard in European industry and diving.
100 psi in bar — nearby values
| Pounds Per Square Inch | Bar | Unrounded |
|---|---|---|
| 94 psi | 6.4810719 | 6.481071856 |
| 95 psi | 6.5500194 | 6.550019429 |
| 96 psi | 6.618967 | 6.618967001 |
| 97 psi | 6.6879146 | 6.687914574 |
| 98 psi | 6.7568621 | 6.756862147 |
| 99 psi | 6.8258097 | 6.82580972 |
| 100 psi | 6.8947573 | 6.894757293 |
| 101 psi | 6.9637049 | 6.963704866 |
| 102 psi | 7.0326524 | 7.032652439 |
| 103 psi | 7.1016 | 7.101600012 |
| 104 psi | 7.1705476 | 7.170547585 |
| 105 psi | 7.2394952 | 7.239495158 |
| 106 psi | 7.3084427 | 7.308442731 |
Exact factor: 1 pound per square inch = 0.0689475729317 bar. The row for 100 psi is the value this page is about.