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Convert °C, °F, and K with the correct offset formulas.
Convert temperatures between Celsius, Fahrenheit, and Kelvin with the correct offset formulas. Whether it's weather, cooking, or a science assignment, you get the right answer — including below-freezing and absolute-zero edge cases.
Temperature is the only everyday quantity with scales that have different zero points, which makes its conversion a two-step affair rather than a single multiplication. Celsius sets 0 at water's freezing point and 100 at its boiling point (at standard pressure). Fahrenheit, still used in the United States, sets those landmarks at 32 and 212. Kelvin, the scientific scale, starts at absolute zero — the coldest physically possible temperature — so 0 K equals -273.15 C, and its degree increments match Celsius exactly.
The formulas: Fahrenheit = Celsius x 9/5 + 32; Celsius = (Fahrenheit - 32) x 5/9; Kelvin = Celsius + 273.15. The order of operations matters: for F to C, subtract 32 first, then multiply by 5/9 — doing it backwards gives a wrong answer. A handy pair of anchors: -40 is where both scales meet (-40 C = -40 F), and normal human body temperature is 37 C = 98.6 F. Note the subtlety with temperature differences: a rise of 10 Celsius degrees is a rise of 18 Fahrenheit degrees, but you do not add 32 when converting a difference — the offset applies only to absolute temperatures.
Everyday contexts cluster around a few landmarks worth memorizing. Weather: 0 C = 32 F (freezing), 20 C = 68 F (pleasant room), 30 C = 86 F (hot), 40 C = 104 F (dangerous heat). Cooking: 180 C = 356 F (moderate oven), 200 C = 392 F, 220 C = 428 F. Science and engineering: always Kelvin for gas laws and thermodynamics, because the formulas require an absolute scale. This calculator handles all three scales in both directions.
Conversions go through Celsius: °F → °C is (°F − 32) × 5/9, and K → °C is K − 273.15; going back, °C → °F is °C × 9/5 + 32 and °C → K is °C + 273.15.
Multiply by 9/5, then add 32: 20 x 9/5 = 36; 36 + 32 = 68 F. Reverse check: (68 - 32) x 5/9 = 36 x 5/9 = 20 C. This is the thermostat conversion Americans abroad and Europeans in America perform constantly. Nearby anchors: 18 C = 64.4 F, 22 C = 71.6 F, 25 C = 77 F — so a European hotel room set to 22 C feels like 72 F to an American guest, perfectly comfortable either way.
Subtract 32 first: 350 - 32 = 318. Multiply by 5/9: 318 x 5/9 = 1,590/9 = 176.67, rounded to 177 C. American recipes calling for 350 F want a 177 C oven — in practice, 175 C or 180 C on a European dial, since most ovens are no more accurate than a few degrees anyway. The reverse trip: a French recipe's 200 C is 200 x 9/5 + 32 = 392 F, so an American cook sets 400 F and watches the food rather than the dial.
212 °F. Enter 100, choose °C → °F — the formula is 100 × 9/5 + 32.
No. Temperature scales have different zero points, so you can't just multiply — the calculator uses the proper offset formulas for every conversion.
−273.15 °C, which is 0 Kelvin. The calculator handles it fine — try entering 0 K.