Weather converter
Barometric Pressure Converter
How the barometric pressure converter works
US weather reports use inches of mercury, the rest of the world uses hectopascals (identical to millibars), and aviation altimeters mix both. Enter a pressure in any unit to see all the others.
1 inHg = 33.864 hPa 1 atm = 1013.25 hPa 1 hPa = 1 mbQuick tips
- Memorize one number: 1013.25 hPa = 29.92 inHg. Everything else is relative to it.
- The trend beats the value: a steady 1005 hPa is calmer weather than 1015 hPa falling fast.
- hPa and mb are identical - no conversion needed, only the name changed.
Pressure conversion chart
| hPa | inHg | mmHg | kPa | atm | psi |
|---|---|---|---|---|---|
| 950 | 28.05 | 712.56 | 95 | 0.94 | 13.78 |
| 980 | 28.94 | 735.06 | 98 | 0.97 | 14.21 |
| 1,000 | 29.53 | 750.06 | 100 | 0.99 | 14.5 |
| 1,013 | 29.92 | 760 | 101.33 | 1 | 14.7 |
| 1,020 | 30.12 | 765.07 | 102 | 1.01 | 14.79 |
| 1,040 | 30.71 | 780.07 | 104 | 1.03 | 15.08 |
| 1,050 | 31.01 | 787.57 | 105 | 1.04 | 15.23 |
Pressure reference points
| Reading | hPa | inHg | Meaning |
|---|---|---|---|
| Strongest recorded high | 1,084 | 32.01 | Agata, Siberia (1968) |
| Strong high pressure | 1,040 | 30.71 | Settled, clear weather |
| Standard sea level | 1,013.25 | 29.92 | Baseline for altimeters |
| Deep low / storm | 980 | 28.94 | Wind and precipitation likely |
| Major hurricane core | 920 | 27.17 | Category 5 territory |
| Lowest ever recorded | 870 | 25.69 | Typhoon Tip (1979) |
Frequently asked questions
Are hectopascals and millibars the same?
Yes - 1 hPa equals exactly 1 mb. Meteorology renamed millibars to hectopascals when adopting SI units; the numbers never changed.
What is normal barometric pressure in inHg?
29.92 inHg (1013.25 hPa) at sea level. Everyday weather typically swings between about 28.9 and 30.7 inHg.
Why do altimeters need a pressure setting?
Aircraft altimeters infer altitude from pressure, so pilots dial in the local sea-level pressure (QNH) to read true altitude as weather systems move through.