{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"boiling-point-altitude"},"result":{"entity_type":"calculator","id":"boiling-point-altitude","calculator_id":"boiling-point-altitude","canonical_url":"https://tttkmbb.com/weather/boiling-point-altitude","name":"Boiling Point at Altitude Calculator","title":"Boiling Point of Water at Altitude Calculator – Standard Atmosphere Pressure and Antoine Equation","category":"weather","category_name":"Weather & Environment","tool_name":"calculate_boiling_point_at_altitude","featured_mcp_tool":false,"description":"Computes the boiling point of water at a given altitude by taking the ISA pressure at that altitude (or a measured station pressure) and solving the Antoine equation for water, with a note on cooking at altitude.","use_when":"You need the boiling temperature of water at your elevation for cooking, canning, brewing, candy making or laboratory work, or the boiling point at a measured barometric pressure.","do_not_use_when":"You need the boiling point of a liquid other than water or of salt/sugar solutions (boiling-point elevation), or altitudes above 9000 m.","inputs":[{"name":"altitude","label":"Altitude","type":"number","required":true,"min":-1640,"max":29500,"description":"Elevation above sea level in altitude_unit (−500 to 9000 m).","example":1500},{"name":"altitude_unit","label":"Altitude unit","type":"enum","required":false,"default":"m","values":[{"value":"m","label":"Metres","aliases":["metre","meter","metres","meters"]},{"value":"ft","label":"Feet","aliases":["foot","feet"]}],"description":"Unit of the altitude input.","example":"m"},{"name":"pressure_hpa","label":"Measured station pressure (optional)","type":"number","unit":"hPa","required":false,"min":200,"max":1100,"description":"Actual absolute pressure at the site in hPa; when given it replaces the standard-atmosphere pressure for the altitude.","example":845.56}],"outputs":[{"name":"boiling_point_c","label":"Boiling point","type":"number","unit":"°C","decimals":1,"description":"Boiling temperature of pure water at the site pressure."},{"name":"boiling_point_f","label":"Boiling point","type":"number","unit":"°F","decimals":1,"description":"Boiling point in Fahrenheit."},{"name":"boiling_point_drop_c","label":"Below sea-level boiling point","type":"number","unit":"°C","decimals":1,"description":"100 °C minus the local boiling point."},{"name":"pressure_hpa","label":"Pressure used","type":"number","unit":"hPa","decimals":1,"description":"Standard-atmosphere pressure at the altitude, or the measured pressure if supplied."},{"name":"pressure_mmhg","label":"Pressure used","type":"number","unit":"mmHg","decimals":1,"description":"Same pressure in millimetres of mercury."},{"name":"altitude_m","label":"Altitude","type":"number","unit":"m","decimals":0,"description":"Altitude in metres."},{"name":"altitude_ft","label":"Altitude","type":"number","unit":"ft","decimals":0,"description":"Altitude in feet."},{"name":"cooking_note","label":"Cooking note","type":"string","decimals":4,"description":"Practical consequence for boiling and simmering food at this altitude."}],"input_schema":{"type":"object","properties":{"altitude":{"description":"Elevation above sea level in altitude_unit (−500 to 9000 m).","type":"number","minimum":-1640,"maximum":29500,"examples":[1500]},"altitude_unit":{"description":"Unit of the altitude input.","type":"string","enum":["m","ft"],"default":"m","examples":["m"]},"pressure_hpa":{"description":"Actual absolute pressure at the site in hPa; when given it replaces the standard-atmosphere pressure for the altitude. Unit: hPa.","type":"number","minimum":200,"maximum":1100,"examples":[845.56],"x-unit":"hPa"}},"additionalProperties":false,"required":["altitude"]},"output_schema":{"type":"object","properties":{"boiling_point_c":{"description":"Boiling temperature of pure water at the site pressure. Unit: °C.","type":"number","x-unit":"°C"},"boiling_point_f":{"description":"Boiling point in Fahrenheit. Unit: °F.","type":"number","x-unit":"°F"},"boiling_point_drop_c":{"description":"100 °C minus the local boiling point. Unit: °C.","type":"number","x-unit":"°C"},"pressure_hpa":{"description":"Standard-atmosphere pressure at the altitude, or the measured pressure if supplied. Unit: hPa.","type":"number","x-unit":"hPa"},"pressure_mmhg":{"description":"Same pressure in millimetres of mercury. Unit: mmHg.","type":"number","x-unit":"mmHg"},"altitude_m":{"description":"Altitude in metres. Unit: m.","type":"number","x-unit":"m"},"altitude_ft":{"description":"Altitude in feet. Unit: ft.","type":"number","x-unit":"ft"},"cooking_note":{"description":"Practical consequence for boiling and simmering food at this altitude.","type":"string"}}},"formula":"p = 1013.25 × (1 − 0.0065·h/288.15)^5.25578 hPa (ISA); P_mmHg = p / 1.333224; T_boil = 1730.63 / (8.07131 − log10(P_mmHg)) − 233.426 °C (Antoine equation for water, valid 1–100 °C)","method":"The standard atmosphere is an average; on a given day the real pressure, and hence the boiling point, varies by about ±0.5 °C with weather. Rule of thumb: the boiling point falls about 1 °C per 300 m (1 °F per 500 ft).","sources":[{"name":"Wikipedia – Antoine equation (water coefficients, 1–100 °C)","url":"https://en.wikipedia.org/wiki/Antoine_equation","type":"reference","retrieved_at":"2026-09-24"},{"name":"Wikipedia – International Standard Atmosphere (ICAO Doc 7488)","url":"https://en.wikipedia.org/wiki/International_Standard_Atmosphere","type":"reference","retrieved_at":"2026-09-24"},{"name":"Wikipedia – High-altitude cooking (boiling point table)","url":"https://en.wikipedia.org/wiki/High-altitude_cooking","type":"reference","retrieved_at":"2026-09-24"}],"freshness":{"type":"static","max_age_seconds":null,"note":"Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output."},"examples":[{"name":"1500 m","inputs":{"altitude":1500,"altitude_unit":"m"},"expected":{"boiling_point_c":95,"boiling_point_f":203,"boiling_point_drop_c":5,"pressure_hpa":845.6,"pressure_mmhg":634.2,"altitude_ft":4921},"url":"https://tttkmbb.com/api/v1/calculate/boiling-point-altitude?altitude=1500&altitude_unit=m"},{"name":"Denver, 5280 ft","inputs":{"altitude":5280,"altitude_unit":"ft"},"expected":{"boiling_point_c":94.7,"boiling_point_f":202.4,"altitude_m":1609,"pressure_hpa":834.3},"url":"https://tttkmbb.com/api/v1/calculate/boiling-point-altitude?altitude=5280&altitude_unit=ft"}],"faq":[{"q":"Why does food take longer to cook at altitude?","a":"Boiling water is cooler, so heat transfers into the food more slowly; pasta, rice, beans and eggs need more time and often more liquid, and some foods never soften without a pressure cooker."},{"q":"Does adding salt raise the boiling point noticeably?","a":"Barely: a typical 1 % kitchen brine raises it by about 0.2 °C, far less than the drop from a few hundred metres of elevation."},{"q":"Which pressure should I enter?","a":"The absolute (station) pressure read at the site, not the sea-level-corrected value from weather reports; leave it empty to use the standard atmosphere."}],"tags":["boiling point altitude","water boiling temperature elevation","high altitude cooking","antoine equation","boiling point pressure"],"related":[{"calculator_id":"pressure-altitude","reason":"Standard pressure at an altitude and station pressure from QNH."},{"calculator_id":"turkey-cooking-time","reason":"Roasting times also change with altitude and oven temperature."},{"calculator_id":"temperature","reason":"Convert the boiling point between °C and °F."}],"links":{"html":"https://tttkmbb.com/weather/boiling-point-altitude","markdown":"https://tttkmbb.com/weather/boiling-point-altitude.md","json":"https://tttkmbb.com/weather/boiling-point-altitude.json","api":"https://tttkmbb.com/api/v1/calculate/boiling-point-altitude","schema":"https://tttkmbb.com/api/v1/calculators/boiling-point-altitude","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T01:49:57Z"}