This converter turns millibars into pounds per square inch instantly, using the exact factor 1 millibar = 0.01450377377 pounds per square inch. Type any number and the result updates as you go — nothing is sent to a server, so the arithmetic happens entirely in your browser.
The meteorologist’s unit — sea-level pressure averages 1013.25 mbar. The dominant US pressure unit for tyres, plumbing and compressors.
Because the relationship is a simple proportion, one multiplication does the whole job. The table further down gives pre-computed values for the amounts people look up most often, and the result panel also reports the reverse conversion so you can check the figure both ways.
The formula
millibars- The amount you are converting, measured in millibars
0.01450377377- The exact number of pounds per square inch in one millibar
pounds per square inch- The converted result
How it works, step by step
- Enter the number of millibars you want to convert.
- The value is multiplied by 0.01450377377, the exact conversion factor.
- The result is displayed in pounds per square inch, rounded for readability.
- The unrounded value and the reverse conversion appear underneath so you can verify it.
Worked examples
Converting 5 millibars
Multiply 5 by 0.014503774. That gives 0.072519 pounds per square inch. A quick sanity check: one millibar is smaller than one pound per square inch, so the number should get smaller — and it does.
Converting 72 millibars
72 × 0.014503774 = 1.0443 pounds per square inch. Working backwards, 1.0443 ÷ 0.014503774 returns 72 millibars, which confirms the factor is applied the right way round.
How to read your score
Frequently asked questions
How many pounds per square inch are in one millibar?
Exactly 0.01450377377. Every conversion on this page is that single number multiplied by your input, so the result carries no rounding error beyond what is shown.
What is the formula to convert millibars to pounds per square inch?
Pounds Per Square Inch = millibars × 0.01450377377. To reverse it, divide instead: millibars = pounds per square inch ÷ 0.01450377377, which is the same as multiplying by 68.94757293.
Is the millibar bigger than the pound per square inch?
No. One millibar is only 0.0145038 of a pound per square inch, so the pound per square inch is the larger unit.
Why does my answer differ slightly from other millibar to psi converters?
Most differences come from rounding the factor too early. This tool keeps full double precision through the calculation and only rounds at the final display step, and it also shows the unrounded value so you can see exactly where any difference appears.
What is a millibar?
The meteorologist’s unit — sea-level pressure averages 1013.25 mbar.
What is a pound per square inch?
The dominant US pressure unit for tyres, plumbing and compressors.
Millibars to pounds per square inch reference table
| Millibars | Pounds Per Square Inch |
|---|---|
| 0.5 mbar | 0.007252 psi |
| 1 mbar | 0.014504 psi |
| 2 mbar | 0.029008 psi |
| 3 mbar | 0.043511 psi |
| 5 mbar | 0.072519 psi |
| 10 mbar | 0.145038 psi |
| 15 mbar | 0.217557 psi |
| 20 mbar | 0.290075 psi |
| 25 mbar | 0.362594 psi |
| 50 mbar | 0.725189 psi |
| 75 mbar | 1.0878 psi |
| 100 mbar | 1.4504 psi |
| 250 mbar | 3.6259 psi |
| 500 mbar | 7.2519 psi |
| 1000 mbar | 14.5038 psi |
Exact factor: 1 millibar = 0.01450377377 pounds per square inch. Values rounded for display.