Free tool
Barometric pressure converter
Type a value in any unit and the others update instantly. Weather pressure in the US is in inches of mercury (inHg); most of the world uses hectopascals (hPa), which are the same as millibars (mb).
Standard atmosphere in every unit
| Unit | 1 atm equals | 1 hPa equals |
|---|---|---|
| inHg (inches of mercury) | 29.9213 | 0.02953 |
| hPa (hectopascals) | 1013.25 | 1 |
| mb (millibars) | 1013.25 | 1 |
| mmHg (millimeters of mercury) | 759.9999 | 0.75006 |
| kPa (kilopascals) | 101.325 | 0.1 |
| psi (pounds per square inch) | 14.6959 | 0.014504 |
| atm (atmospheres) | 1 | 0.00098692 |
Conversion formulas
- inHg = hPa ÷ 33.8639
- hPa = inHg × 33.8639
- mmHg = hPa × 0.750062
- kPa = hPa ÷ 10
- psi = inHg × 0.491154
- 1 mb = 1 hPa = 100 Pa
Converters for one pair
Frequently asked questions
How do I convert hPa to inHg?
Divide by 33.8639. For example, 1013.25 hPa ÷ 33.8639 = 29.92 inHg. To go from inHg to hPa, multiply by 33.8639.
Are millibars and hectopascals the same?
Yes. 1 millibar (mb) equals exactly 1 hectopascal (hPa), so 1013 mb is 1013 hPa. Weather services switched the name to hPa, but the number is identical.
What is standard atmospheric pressure in every unit?
1 atm = 1013.25 hPa = 1013.25 mb = 29.921 inHg = 760 mmHg = 101.325 kPa = 14.696 psi.
Which unit should I use for barometric pressure?
Use inHg in the US (weather reports and aviation), hPa or mb almost everywhere else, and mmHg in some countries such as Russia. kPa is common in Canada; psi is mostly for tires and engineering, not weather.