Convert an altitude in feet or metres of height above sea level to a pressure reading in millibar (mbar, mb or mbr), pounds per square inch (psi), millimetres of mercury at zero degrees celsius (mmHg @ 0 deg C) or inches of mercury at zero degrees celsius (inHg @ 0 deg C).
| ft | m | mbar | psi | mmHg | inHg |
|---|---|---|---|---|---|
| -5000 | -1524.0 | 1210.23 | 17.553 | 907.75 | 35.738 |
| -4000 | -1219.2 | 1168.55 | 16.948 | 876.48 | 34.507 |
| -3000 | -914.40 | 1128.03 | 16.361 | 846.09 | 33.311 |
| -2000 | -609.60 | 1088.66 | 15.790 | 816.56 | 32.148 |
| -1000 | -304.80 | 1050.41 | 15.235 | 787.87 | 31.018 |
| -900 | -274.32 | 1046.64 | 15.180 | 785.05 | 30.907 |
| -800 | -243.84 | 1042.89 | 15.126 | 782.23 | 30.796 |
| -700 | -213.36 | 1039.15 | 15.072 | 779.42 | 30.686 |
| -600 | -182.88 | 1035.41 | 15.017 | 776.62 | 30.576 |
| -500 | -152.40 | 1031.69 | 14.963 | 773.83 | 30.466 |
| -400 | -121.92 | 1027.98 | 14.910 | 771.05 | 30.356 |
| -300 | -91.440 | 1024.28 | 14.856 | 768.28 | 30.247 |
| -200 | -60.960 | 1020.59 | 14.802 | 765.51 | 30.138 |
| -100 | -30.480 | 1016.92 | 14.749 | 762.75 | 30.030 |
| -50 | -15.240 | 1015.08 | 14.723 | 761.37 | 29.975 |
| 0 | 0 | 1013.25 | 14.696 | 760.00 | 29.921 |
| 50 | 15.240 | 1011.42 | 14.669 | 758.63 | 29.867 |
| 100 | 30.480 | 1009.59 | 14.643 | 757.26 | 29.813 |
| 200 | 60.960 | 1005.95 | 14.590 | 754.52 | 29.706 |
| 300 | 91.440 | 1002.31 | 14.537 | 751.80 | 29.598 |
| 400 | 121.92 | 998.689 | 14.485 | 749.08 | 29.491 |
| 500 | 152.40 | 995.075 | 14.432 | 746.37 | 29.385 |
| 600 | 182.88 | 991.472 | 14.380 | 743.67 | 29.278 |
| 700 | 213.36 | 987.880 | 14.328 | 740.97 | 29.172 |
| 800 | 243.84 | 984.298 | 14.276 | 738.28 | 29.066 |
| 900 | 274.32 | 980.727 | 14.224 | 735.61 | 28.961 |
| 1000 | 304.80 | 977.166 | 14.173 | 732.93 | 28.856 |
| 2000 | 609.60 | 942.129 | 13.664 | 706.65 | 27.821 |
| 3000 | 914.40 | 908.117 | 13.171 | 681.14 | 26.817 |
| 4000 | 1219.2 | 875.105 | 12.692 | 656.38 | 25.842 |
| 5000 | 1524.0 | 843.073 | 12.228 | 632.36 | 24.896 |
| 6000 | 1828.8 | 811.996 | 11.777 | 609.05 | 23.978 |
| 7000 | 2133.6 | 781.854 | 11.340 | 586.44 | 23.088 |
| 8000 | 2438.4 | 752.624 | 10.916 | 564.51 | 22.225 |
| 9000 | 2743.2 | 724.285 | 10.505 | 543.26 | 21.388 |
| 10000 | 3048.0 | 696.817 | 10.106 | 522.66 | 20.577 |
| 15000 | 4572.0 | 571.820 | 8.2935 | 428.90 | 16.886 |
| 20000 | 6096.0 | 465.633 | 6.7534 | 349.25 | 13.750 |
| 25000 | 7620.0 | 376.009 | 5.4536 | 282.03 | 11.104 |
| 30000 | 9144.0 | 300.896 | 4.3641 | 225.69 | 8.8855 |
| 35000 | 10668 | 238.423 | 3.4580 | 178.83 | 7.0406 |
| 40000 | 12192 | 187.54 | 2.7200 | 140.67 | 5.5381 |
| 45000 | 13716 | 147.48 | 2.1390 | 110.62 | 4.3550 |
| 50000 | 15240 | 115.97 | 1.6821 | 86.987 | 3.4247 |
| 55000 | 16764 | 91.199 | 1.3227 | 68.405 | 2.6931 |
| 60000 | 18288 | 71.717 | 1.0402 | 53.792 | 2.1178 |
| 65000 | 19812 | 56.397 | 0.8180 | 42.301 | 1.6654 |
| 70000 | 21336 | 44.377 | 0.6436 | 33.286 | 1.3105 |
| 75000 | 22860 | 34.978 | 0.5073 | 26.236 | 1.0329 |
| 80000 | 24384 | 27.615 | 0.4005 | 20.713 | 0.8155 |
| 85000 | 25908 | 21.837 | 0.3167 | 16.379 | 0.6448 |
| 90000 | 27432 | 17.296 | 0.2509 | 12.973 | 0.5107 |
| 95000 | 28956 | 13.721 | 0.1990 | 10.291 | 0.4052 |
| 100000 | 30480 | 10.902 | 0.1581 | 8.1769 | 0.3219 |
The height relative to sea level conversions are derived using the US Standard Atmosphere 1976 barometric formula for geopotential altitude with the following values[1-6] at heights from 5,000 ft (1524 m) below to 100,000 ft (30,480 m) above mean sea level.
- Standard atmospheric pressure of 1013.25 mb at 0 m, 226.321 mb at 11,000 m, 54.7489 mb at 20,000 m above mean sea level.
- Standard temperature of 288.15K (15°C) at 0 m, 216.65K (-56.5°C) at 11,000 m and 20,000 m above mean sea level.
- Standard thermal gradient or lapse rate of -0.0065 K/m from 0 to 11,000 m, 0 K/m from 11,000 to 20,000 m, 0.001 k/m from 20,000 to 32,000 m above mean sea level.
- Standard acceleration due to gravity of 9.80665 m/s².
- Gas constant for air of 8.31432 J/Kmol K.
- Molar mass of air of 0.0289644 kg/mole.
n.b. Please note that the calculated altitude values are not absolute precise conversions and should not be treated as such.