Temperature converter
Celsius, Fahrenheit and kelvin in both directions, with the formulas shown.
Options
This is below absolute zero (−273.15 °C, −459.67 °F, 0 K); nothing real can be that cold. Check the sign.
Raw value:
In every unit
| Unit | Value |
|---|---|
| Celsius (°C) | – |
| Fahrenheit (°F) | – |
| Kelvin (K) | – |
kB, MB, GB and TB are decimal (1 kB = 1000 B), as on drive labels and mobile plans. KiB, MiB, GiB and TiB are binary (1 KiB = 1024 B), as Windows shows file sizes. Bits are for connection speeds; 8 bits make a byte.
A month is the average Gregorian month of 30.436875 days and a year is 365.2425 days; calendar months and years vary.
US units follow the US customary system (1 gal = 3.785 L, 1 cup = 236.6 mL); UK units follow the imperial system (1 gal = 4.546 L).
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Unit converter
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Area converter
Square meters, square feet, acres and hectares, converted as you type. -
Volume converter
Milliliters, liters, US and UK gallons, cups and fluid ounces, converted as you type. -
Speed converter
Kilometers per hour, miles per hour, knots, m/s and ft/s, converted as you type. -
Time converter
From nanoseconds to years, converted as you type, with the average month and year stated. -
Data size converter
Bytes, kB, MB, GB, KiB, MiB, GiB and bits, with 1000 and 1024 kept apart.
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Temperature is the one conversion you cannot do by multiplying alone, because the scales start at different points: 0 °C is 32 °F, and a change of 1 °C is a change of 1.8 °F. This page does the arithmetic for a weather forecast abroad, an oven set in the other scale, a fever read on a foreign thermometer or a lab value in kelvin. Type the temperature, pick the scales, and the result and the table update as you type, so 180 °C shows as 356 °F and 453.15 K together. Values below absolute zero are flagged. Nothing is sent anywhere.
How to use
- Type the temperature, for example 180.
- Choose the scale you have and the one you want; Celsius to Fahrenheit is preset.
- Press swap to go from Fahrenheit to Celsius.
- Read the kelvin value in the table if you need it.
What it handles
- Celsius, Fahrenheit and kelvin, converted with the exact formulas: F = C × 9/5 + 32 and K = C + 273.15.
- Negative values work, with an ordinary hyphen or a proper minus sign, so -40 gives -40 in both scales.
- Warns when a value is below absolute zero (-273.15 °C, -459.67 °F, 0 K) but still shows the arithmetic.
- Decimal comma or point, so 37,5 and 37.5 both give 99.5 °F.
FAQ
What is the formula for Celsius to Fahrenheit?
Multiply by 9, divide by 5, add 32: 20 °C is 20 × 9 ÷ 5 + 32 = 68 °F. Going back, subtract 32, multiply by 5 and divide by 9: 68 °F is (68 − 32) × 5 ÷ 9 = 20 °C. For a quick estimate in your head, double the Celsius value and add 30, which is within a few degrees for room and outdoor temperatures.
What is 180 °C in Fahrenheit for an oven?
356 °F, which most ovens marked in Fahrenheit round to 350 °F. Common pairs: 160 °C is 320 °F, 200 °C is 392 °F (use 400 °F), 220 °C is 428 °F (use 425 °F). Fan ovens usually run about 20 °C hotter than the dial in a conventional oven, so a recipe written for fan assist at 160 °C means roughly 180 °C conventional.
What is a normal body temperature in Fahrenheit?
37 °C is 98.6 °F, and anything between about 36.1 °C and 37.2 °C (97 °F to 99 °F) is normal for most adults. A reading of 38 °C is 100.4 °F, which is the usual threshold for a fever. Thermometers vary by where they measure, under the arm, in the ear or on the forehead, so compare like with like.
Why does the page warn about absolute zero?
Absolute zero, 0 K, is the lowest temperature possible; it is -273.15 °C or -459.67 °F. A value below it cannot describe a real thing, so the page flags it in case a sign or a digit was mistyped. The result is still shown, because the formula works on any number and the warning is only a hint.
Why is it kelvin and not degrees kelvin?
Since 1967 the unit has simply been the kelvin, symbol K, with no degree sign, because it is an absolute scale that starts at zero rather than a scale with an arbitrary zero. A kelvin is the same size as a degree Celsius, so converting is just adding or subtracting 273.15, and a difference of 10 K is a difference of 10 °C.
Updated