Boiling Point at Altitude Calculator
Estimate the temperature at which pure water boils as elevation changes. Enter altitude in meters or feet and get boiling point in °C, °F and K, plus estimated atmospheric pressure.
Enter Your Altitude
How the Boiling Point at Altitude Calculator Works
Water boils when its vapor pressure reaches the surrounding atmospheric pressure. At higher elevations, atmospheric pressure is lower, so water reaches that condition at a lower temperature than it does at sea level.
Your selected unit is converted to meters so one consistent pressure model can be used.
The standard-atmosphere equation estimates pressure at that elevation.
The water vapor-pressure relationship is inverted to estimate the boiling point.
Pressure from altitude
For the lower atmosphere, this calculator uses the standard tropospheric pressure relationship:
P is pressure in Pa and h is geometric altitude in meters.
Water boiling point from pressure
The result is estimated with the Antoine vapor-pressure equation for water. For high-altitude conditions below normal atmospheric pressure, the common 1–100 °C water constants are used.
For water: A = 8.07131, B = 1730.63 and C = 233.426.
Water Boiling Point by Altitude
These approximate values show why cooking and boiling behavior changes noticeably at high elevation.
| Altitude | Approx. pressure | Boiling point °C | Boiling point °F |
|---|
Why Does Water Boil at a Lower Temperature at High Altitude?
Boiling is controlled by pressure, not altitude directly. Elevation matters because the column of air above you becomes smaller as you climb, which reduces atmospheric pressure. With less external pressure to overcome, water can form stable vapor bubbles at a lower temperature.
Does this affect cooking?
Yes. Even though water may start boiling sooner at high altitude, the boiling water itself is cooler. Foods cooked by boiling or simmering can therefore take longer because they are being heated at a lower maximum water temperature.
Does salt change the result?
Yes, dissolved substances can raise the boiling point slightly. This calculator is designed for pure water and altitude-driven pressure changes, so it does not apply a salt, sugar or other dissolved-solute correction.
Frequently Asked Questions
What is the boiling point of water at sea level?
At standard atmospheric pressure, pure water boils at approximately 100 °C or 212 °F.
Why does boiling point decrease with altitude?
Atmospheric pressure decreases as elevation rises. Water therefore needs less thermal energy to reach the vapor pressure required for boiling.
How accurate is a boiling point at altitude calculator?
It is useful for planning and education, but it is still an estimate because real atmospheric pressure changes with weather and local conditions.
Can I enter altitude in feet?
Yes. Choose feet, meters, kilometers or miles and the calculator converts the input before performing the pressure calculation.
Why can high-altitude cooking take longer?
Water boils at a lower temperature at higher elevations, so food cooked in boiling water may receive less heat and require more time.
Does a pressure cooker work differently at altitude?
A pressure cooker raises the pressure inside the vessel, increasing water's boiling point. This calculator models open-air boiling and is not a pressure-cooker sizing tool.