How to Convert PSI to Millibars (psi to mbar)
Pressure conversions are used for tyre pressure (psi or bar), blood pressure readings in mmHg and weather maps in millibars. This guide shows how to convert psi into millibars by hand, with examples and a quick-reference table.
The conversion
To convert psi to millibars, multiply the value by 68.94757. To go the other way, divide by the same number (or multiply by 0.0145037744). For a quick estimate, multiply by about 69.
Millibars = psi × 68.94757
Worked examples
- 3 psi = 206.8427 mbar
- 12.5 psi = 861.8446 mbar
- 75 psi = 5,171.07 mbar
PSI to Millibars table
| PSI | Millibars |
|---|---|
| 1 psi | 68.9476 mbar |
| 2 psi | 137.8951 mbar |
| 5 psi | 344.7378 mbar |
| 10 psi | 689.4757 mbar |
| 20 psi | 1,378.95 mbar |
| 25 psi | 1,723.69 mbar |
| 50 psi | 3,447.38 mbar |
| 100 psi | 6,894.76 mbar |
| 250 psi | 17,236.89 mbar |
| 500 psi | 34,473.78 mbar |
| 1,000 psi | 68,947.57 mbar |
Common questions
Is psi to mbar exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Millibars to PSI converter.
Mistakes to avoid
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Forgetting squared and cubed units
Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.
Background
For everyday use, three or four significant figures are usually enough. Engineering, science and trade documents may need more, and rounding should happen only at the end of a calculation.
Writing the units next to every number while you work is the simplest way to avoid mistakes. If the units do not cancel to leave the one you want, the calculation is set up wrongly.
Singapore adopted the metric system in the 1970s, replacing imperial units and traditional Chinese measures in most official uses. Metric units are now standard in schools, trade and government, but older units survive in property, markets and imported goods.
For any value, use the PSI to Millibars Converter or browse all pressure converters.
Run your own numbers: PSI to Millibars Converter