Editorially reviewedReviewed by Agarapu Ramesh, science educator (chemistry). LinkedIn
Last reviewed: May 2026|Standard temperature conversion formulas
What this calculator does
This calculator estimates the boiling point of water at a given altitude by first estimating atmospheric pressure and then relating that pressure to boiling temperature. It is useful for quick kitchen, field, classroom, and engineering estimates where elevation changes the expected boiling point.
As altitude increases, atmospheric pressure generally falls. Lower pressure means water vapor does not need to push against as much external pressure to form stable bubbles, so boiling begins at a lower temperature. That is why recipes, sterilization, and heating behavior can change at higher elevations.
Inputs explained
Altitude: Enter the elevation above mean sea level in meters or the unit expected by the page.
Atmospheric model: The calculator uses a standard-atmosphere style pressure estimate rather than a live weather observation.
Water assumption: The page is tuned for water and should not be assumed to apply to all liquids without different property data.
How it works / method
The engine estimates pressure from altitude using a standard atmosphere relationship. It then applies a Clausius-Clapeyron-style rearrangement to estimate the boiling temperature that corresponds to that lower pressure. This makes the page fast and practical, but it also means the output is an estimate built on standard assumptions rather than a live barometer reading at your exact location.
The first part estimates pressure from altitude. The second part estimates boiling temperature using a simplified phase-change relationship for water. Local weather pressure, impurities, and vessel conditions can shift the actual boiling point.
Practical note: Boiling point changes with pressure and altitude, but this page uses a standard atmosphere estimate. Actual local pressure on a given day can be higher or lower than the model, so treat the result as an estimate.
Estimate water boiling temperature from elevation.
--
Est. Atmospheric Pressure: --
Step-by-step example
Suppose you are near 2,000 m above sea level. The local pressure is lower than at sea level, so water should boil below 100 C.
Enter 2000 for altitude in meters.
The page estimates the corresponding pressure from the standard atmosphere equation.
It then converts that pressure to an estimated boiling temperature for water.
The output lands in the low-to-mid 90s C rather than 100 C.
That lower boiling point helps explain why cooking and sterilization timing often changes at elevation.
Use cases
High-altitude cooking and food-preparation estimates.
Field science or education demonstrations about pressure and phase change.
Quick engineering sanity checks where pressure changes alter expected boiling behavior.
Comparing how altitude changes boiling temperature before using a full thermodynamic property package.
Assumptions and limitations
The result is specific to water and uses simplified assumptions about atmospheric pressure and latent heat.
Actual local weather pressure can differ from the standard atmosphere estimate at the same altitude.
Dissolved solutes, contamination, vessel pressure, and nucleation behavior can all shift real boiling behavior.
This page is not a replacement for laboratory property tables or process-design software.
If you need a more exact answer, use actual barometric pressure and a reference property source for water rather than altitude alone.
Water Boiling Point Altitude Guide
Use water boiling point altitude guide, water boil point by altitude, or boiling point of water at 6800 feet altitude when pressure changes the boiling temperature. Higher altitude lowers air pressure, so water boils below 212 F / 100 C.
Frequently Asked Questions
At 5,000 feet (about 1,524 m) water boils near 95°C, or roughly 203°F. The reason is straightforward — atmospheric pressure at that altitude drops to about 84 kPa, so water reaches vapour-liquid equilibrium at a lower temperature. Treat this as a working estimate; weather changes pressure too. In Denver, Colorado, at exactly that altitude, recipe books routinely warn that pasta needs longer cooking and cake batter rises differently. Lower boiling point means slower thermal cooking, not faster.
At 10,000 feet (3,048 m) water boils around 90°C, or about 194°F. Atmospheric pressure there is roughly 69 kPa — about two-thirds of sea level — so water molecules escape into vapour at lower kinetic energy. Trekkers in the Himalayas notice this fast. Tea will brew but never feel quite "right," and rice in a regular pot can stay tough. A pressure cooker raises internal pressure and brings boiling back near 100°C, which is why mountain kitchens depend on them.
Two-step workflow. First, convert altitude to pressure using the barometric formula: P = P0(1 − 0.0065h/T0)5.255, where h is altitude in metres and T0 is sea-level temperature in kelvin. Then plug pressure into the Clausius–Clapeyron relation to find the boiling point: 1/Tb = 1/T0 − (R/ΔHvap) ln(P/P0). For quick field work I just use the rule that boiling point drops about 1°C for every 285 m gained, and check it against a calculator only for engineering work.
A useful rule of thumb is roughly 1.8°F (about 1°C) per 1,000 feet, but it is not perfectly linear. Pressure falls faster near the surface than higher up, so the drop is larger in the first few thousand feet and tapers off. For cooking adjustments the rule works fine. For lab calibration, derive the value from local barometric pressure rather than altitude, because weather systems can shift pressure by several kilopascals in a day and that matters more than you would expect.
At standard sea-level pressure of 101.325 kPa (1 atm), pure water boils at 100°C or 212°F. That is the reference point for almost every recipe and lab procedure you will read. The catch is that "sea level" assumes standard atmosphere — a low-pressure storm system can drop your boiling point by half a degree even at the coast. For altitude work, treat 100°C as your anchor and apply the appropriate correction. Solutes such as salt also raise boiling point slightly.
Yes, it reaches boiling temperature faster, because boiling is achieved at a lower temperature. But — and this matters — the food cooks slower. Cooking depends on temperature, not on whether bubbles are forming. A pot rolling at 90°C on a high mountain delivers less thermal energy per second than the same pot at 100°C at the coast. So eggs, rice, and beans all need extended cooking time. This trips up new researchers running outdoor field experiments at altitude.
A liquid boils when its vapour pressure equals the surrounding atmospheric pressure. At sea level, water needs to reach 100°C before its vapour pressure climbs to 101.3 kPa. Lower the surrounding pressure, and that match happens at a lower temperature; raise it, and you need a hotter liquid. This is the principle behind pressure cookers, vacuum distillation in chemistry labs, and the difficulty of boiling an egg on Everest. The Clausius–Clapeyron equation describes the relationship quantitatively.
On the Everest summit at 8,849 m, atmospheric pressure drops to roughly 33 kPa — about a third of sea level — and water boils near 71°C (160°F). That is hot enough to scald you but nowhere near hot enough to cook noodles properly. Climbers carry stoves and pressure cookers for this reason. It is also why dehydration and digestion both become serious issues at extreme altitude: warm water alone cannot reliably sterilise food, and metabolism is already strained.
