Boiling point of water by altitude
Every 500 ft from sea level to 15,000 ft and every 250 m to 5,000 m, with the summit of Everest, computed from the 1976 US Standard Atmosphere by the same code as the boiling point simulator.
What is the boiling point of water at high altitude?
Water boils at 212 °F (100 °C) at sea level and a little under 1 °F lower for every 500 ft of climb, as the air pressure falls. In the 1976 US Standard Atmosphere it boils at 202.8 °F (94.9 °C) at 5,000 ft, 193.7 °F (89.8 °C) at 10,000 ft and 158.4 °F (70.2 °C) on Everest.
Boiling point by altitude in feet
The last column is the CDC’s rolling-boil time for making drinking water safe, which rises from 1 minute to 3 above 6,500 ft.
| Altitude (ft) | Air pressure (psi) | Boiling point (°F) | Boiling point (°C) | Boil drinking water |
|---|---|---|---|---|
| Sea level | 14.70 | 212.0 | 100.0 | 1 minute |
| 500 | 14.43 | 211.0 | 99.5 | 1 minute |
| 1,000 | 14.17 | 210.1 | 99.0 | 1 minute |
| 1,500 | 13.92 | 209.2 | 98.5 | 1 minute |
| 2,000 | 13.66 | 208.3 | 97.9 | 1 minute |
| 2,500 | 13.42 | 207.4 | 97.4 | 1 minute |
| 3,000 | 13.17 | 206.5 | 96.9 | 1 minute |
| 3,500 | 12.93 | 205.6 | 96.4 | 1 minute |
| 4,000 | 12.69 | 204.7 | 95.9 | 1 minute |
| 4,500 | 12.46 | 203.7 | 95.4 | 1 minute |
| 5,000 | 12.23 | 202.8 | 94.9 | 1 minute |
| 5,500 | 12.00 | 201.9 | 94.4 | 1 minute |
| 6,000 | 11.78 | 201.0 | 93.9 | 1 minute |
| 6,500 | 11.56 | 200.1 | 93.4 | 1 minute |
| 7,000 | 11.34 | 199.2 | 92.9 | 3 minutes |
| 7,500 | 11.13 | 198.3 | 92.4 | 3 minutes |
| 8,000 | 10.92 | 197.3 | 91.9 | 3 minutes |
| 8,500 | 10.71 | 196.4 | 91.3 | 3 minutes |
| 9,000 | 10.51 | 195.5 | 90.8 | 3 minutes |
| 9,500 | 10.31 | 194.6 | 90.3 | 3 minutes |
| 10,000 | 10.11 | 193.7 | 89.8 | 3 minutes |
| 10,500 | 9.91 | 192.8 | 89.3 | 3 minutes |
| 11,000 | 9.72 | 191.8 | 88.8 | 3 minutes |
| 11,500 | 9.53 | 190.9 | 88.3 | 3 minutes |
| 12,000 | 9.35 | 190.0 | 87.8 | 3 minutes |
| 12,500 | 9.17 | 189.1 | 87.3 | 3 minutes |
| 13,000 | 8.99 | 188.2 | 86.8 | 3 minutes |
| 13,500 | 8.81 | 187.2 | 86.2 | 3 minutes |
| 14,000 | 8.64 | 186.3 | 85.7 | 3 minutes |
| 14,500 | 8.47 | 185.4 | 85.2 | 3 minutes |
| 15,000 | 8.30 | 184.5 | 84.7 | 3 minutes |
| Everest, 29,032 | 4.57 | 158.4 | 70.2 | 3 minutes |
Boiling point by altitude in meters
Near sea level the boiling point falls by about 1 °C for every 300 m.
| Altitude (m) | Air pressure (kPa) | Boiling point (°C) | Boiling point (°F) |
|---|---|---|---|
| Sea level | 101.33 | 100.0 | 212.0 |
| 250 | 98.36 | 99.1 | 210.5 |
| 500 | 95.46 | 98.3 | 209.0 |
| 750 | 92.63 | 97.5 | 207.5 |
| 1,000 | 89.88 | 96.6 | 206.0 |
| 1,250 | 87.19 | 95.8 | 204.5 |
| 1,500 | 84.56 | 95.0 | 203.0 |
| 1,750 | 82.00 | 94.2 | 201.5 |
| 2,000 | 79.50 | 93.3 | 200.0 |
| 2,250 | 77.07 | 92.5 | 198.5 |
| 2,500 | 74.69 | 91.6 | 197.0 |
| 2,750 | 72.38 | 90.8 | 195.5 |
| 3,000 | 70.12 | 90.0 | 194.0 |
| 3,250 | 67.92 | 89.1 | 192.5 |
| 3,500 | 65.78 | 88.3 | 190.9 |
| 3,750 | 63.69 | 87.5 | 189.4 |
| 4,000 | 61.66 | 86.6 | 187.9 |
| 4,250 | 59.68 | 85.8 | 186.4 |
| 4,500 | 57.75 | 85.0 | 184.9 |
| 4,750 | 55.88 | 84.1 | 183.4 |
| 5,000 | 54.05 | 83.3 | 181.9 |
| Everest, 8,849 | 31.50 | 70.2 | 158.4 |
How each row is worked out
Three steps turn an altitude into a boiling point. The altitude becomes geopotential height, the height in a uniform gravity field that takes the same work to climb, which is what the 1976 standard is written in. Below 11 km the standard gives the air a temperature falling 6.5 K per kilometer from 288.15 K, and a pressure that follows from it. Water then boils where its saturation vapor pressure, from Hyland and Wexler’s 1983 equation, equals that pressure. The equation cannot be inverted by algebra, so the temperature is found by repeated bisection. At 10,000 ft:
Boiling point at 10,000 ft
- z = 10,000 ft × 0.3048 = 3,048 m
- H = r₀z / (r₀ + z) = 6,356,766 × 3,048 / 6,359,814 = 3,046.54 m
- T = 288.15 − 0.0065 × 3,046.54 = 268.35 K
- p = 101.325 × (268.35 / 288.15)^5.255876 = 69.69 kPa, or 10.11 psi
- pws(Tb) = 69.69 kPa at Tb = 89.82 °C = 193.67 °F
The exponent 5.255876 is g₀M/(R*L) with the standard’s own constants: standard gravity 9.80665 m/s², the molar mass of air 0.0289644 kg/mol, its gas constant 8.31432 J/(mol K) and the lapse rate 0.0065 K/m. At sea level the same equation gives 99.97 °C, the boiling point on the modern temperature scale, rather than exactly 100 °C.
Cooking and boiling water at high altitude
For drinking water the CDC gives a time, not a temperature: “Bring clear water to a rolling boil for 1 minute (at elevations above 6,500 feet, boil for 3 minutes).” At 6,500 ft water boils at 200.1 °F (93.4 °C), so a mile-high kitchen is still on the 1-minute side and every row from 7,000 ft up is on the 3-minute side.
Food cooked in boiling water takes longer the higher you go, because the water is cooler, and turning up the burner does not help: boiling water stays at its boiling point. Charles Williams’s formula for a soft-boiled 57 g egg from the fridge gives 4.54 minutes at sea level, 5.16 minutes at 5,000 ft, 5.93 at 10,000 ft and 6.71 at 14,000 ft, and he notes that it under-predicts at altitude.
A pressure cooker raises the boiling point again, but its valve holds the steam a fixed gauge pressure above the air outside, so it too runs cooler up high. At 15 psi it reaches 249.7 °F (120.95 °C) at sea level, 244.8 °F (118.2 °C) at 5,000 ft and 240.3 °F (115.7 °C) at 10,000 ft. Follow your cooker’s and your recipe’s instructions for your elevation; these figures are the physics, not food-safety advice.
Why a real pot can differ from the table
- The weather. The standard atmosphere is an average. Near sea level each kPa of pressure moves the boiling point by 0.28 °C, or 0.50 °F, so a change of one inch of mercury on a barometer moves it by about 1.7 °F.
- Latitude and season. At great heights the air presses harder near the equator than the standard atmosphere allows, and Everest is at 28° N. In October 1981 a barometer on its summit read 253 mmHg, 33.73 kPa, where water boils at 161.3 °F (71.8 °C), 2.9 °F hotter than the table’s Everest row. The same study found the pressure at the summit’s height about 11.5 mmHg higher in midsummer than in midwinter.
- What is dissolved. Salt and sugar raise the boiling point; the freezing point depression calculator works out that boiling point elevation from the molality.
Any altitude or pressure
The boiling point at altitude simulator runs the same model at any altitude from the Dead Sea to 11 km, at any typed pressure, and inside a pressure cooker, with six other liquids alongside water. To convert the pressures here, the pressure conversion table lists every factor, and the heating curve calculator follows water from ice to steam at one atmosphere.
Sources: U.S. Standard Atmosphere, 1976 (NOAA, NASA and the US Air Force); Hyland and Wexler (1983), the saturation curve ASHRAE uses for water; the CDC’s How to Make Water Safe in an Emergency; C. D. H. Williams, The Science of Boiling an Egg, University of Exeter; and West and colleagues (1983) for the barometer reading on Everest.
The values are facts and free to use; this table’s selection and presentation are © 2026 ScienceQuest.