Home›Unit Converters›Temperature Converter

Temperature Converter

This temperature converter links Fahrenheit, Celsius and Kelvin. Type a temperature into any of the three boxes and the other two update live as you type, so a weather forecast abroad, an oven setting in a metric cookbook or a fever reading is translated the moment you enter it.

Built & reviewed by the TurboTeamTools team · Updated September 2026 · 0 uses on this device

Temperature Converter tool

Common temperatures

Reference°F°C
Water freezes320
Room temperature68–7220–22
Body temperature98.637
Water boils (sea level)212100
Absolute zero−459.67−273.15

How to use it

  1. Type a temperature into any of the three boxes.
  2. The other two scales fill in as you type.
  3. Check the reference table for everyday temperatures.

What is temperature conversion?

Temperature conversion moves a reading between scales that place their zero points differently. Fahrenheit and Celsius are the everyday pair, and the formula subtracts the offset before scaling:

°C = (°F - 32) × 5/9

A 72 °F room works out to (72 minus 32) × 5/9, which is 22.2 °C. Going the other way, multiply by 9/5 and add 32, so 20 °C is 68 °F. Kelvin, the scientific scale, is simply Celsius plus 273.15 and never goes negative. Because the two everyday scales cross at minus 40, that is the one temperature where Fahrenheit and Celsius read the same.

Worked example

Input: 72 °F
→
Result: 22.2 °C
Input: 100 °C
→
Result: 212 °F

Oven temperatures: Fahrenheit, Celsius and gas mark

°F°C (exact)Gas mark
2751351
3001492
3251633
3501774
3751915
4002046
4252187
4502328
4752469

Celsius values are exact conversions; metric cookbooks usually round them, so 350 °F appears as 180 °C.

Fahrenheit, Celsius and Kelvin

To convert Fahrenheit to Celsius, subtract 32 and multiply by 5/9. Going the other way, multiply by 9/5 and add 32. A 72 °F room is (72 − 32) × 5/9, which is 22.2 °C; a 20 °C day is 20 × 1.8 + 32, or 68 °F. Water freezes at 32 °F, which is 0 °C, and boils at 212 °F, which is 100 °C, so the two scales cross at −40, where the numbers are equal. A change of one Celsius degree is a change of 1.8 Fahrenheit degrees.

For a rough answer without a calculator, double the Celsius figure and add 30: 20 °C becomes 70, close to the true 68. Run it backwards by subtracting 30 from Fahrenheit and halving, so 90 °F is about 30 °C (the exact value is 32.2). The shortcut stays within a few degrees between freezing and body temperature, which covers most weather.

Kelvin, ovens and fevers

Kelvin uses the same size degree as Celsius but starts at absolute zero, the coldest possible temperature, so it never goes negative. Add 273.15 to a Celsius reading to get Kelvin: 25 °C is 298.15 K, and absolute zero is −273.15 °C or −459.67 °F. Scientists use it for gas laws and thermodynamics, and it is written without a degree sign. US engineers sometimes use the Rankine scale, which also starts at absolute zero but counts in Fahrenheit-sized degrees.

Oven settings are the other daily conversion. A 350 °F oven is 177 °C, usually rounded to 180 °C in metric cookbooks; 400 °F is 204 °C and 425 °F is 218 °C. Convection or fan ovens typically need about 25 °F less than the stated temperature, and metric recipes usually say 20 °C less. For health, 98.6 °F (37 °C) is the traditional average body temperature, and 100.4 °F (38 °C) is the threshold most clinics use to call a reading a fever.

Common uses

  • Converting weather forecasts abroad
  • Following recipes with the other scale's oven temperature
  • Science homework and lab work
  • Checking a fever reading in either scale
  • Setting a thermostat or water heater in the other unit
  • Reading engine, CPU and appliance temperatures

When to use it

  • You are traveling and want to convert 30 degrees Celsius to Fahrenheit before packing (it is 86 °F).
  • A British recipe says gas mark 4 and your oven dial reads Fahrenheit.
  • A thermometer shows 38.5 °C and you want the fever reading in Fahrenheit (101.3 °F).
  • Chemistry homework needs the answer in Kelvin, not Celsius.
  • You are setting a thermostat or water heater whose dial uses the scale you do not think in.

Related tools

The Volume Converter handles the cups and milliliters in the same metric recipe.

The Weight Converter turns its grams of flour into ounces.

The Speed Converter reads the wind half of a foreign weather report, in knots or km/h.

Frequently asked questions

Subtract 32 from the Fahrenheit value, then multiply by 5/9. For 72 °F, that is 40 times 5/9, which is about 22.2 °C. Multiplying by 0.5556 gives the same result as 5/9 if you prefer a decimal. For a fast estimate, subtract 30 and halve.
Multiply the Celsius value by 9/5 and add 32. For 20 °C, that is 36 plus 32, which is 68 °F. Since 9/5 is 1.8, a 30 °C beach day is 30 × 1.8 + 32, or 86 °F, and a 0 °C freeze is 32 °F.
About 177 °C, which metric recipes round to 180 °C. Other common oven settings: 325 °F is 163 °C, 375 °F is 190 °C, 400 °F is 204 °C and 450 °F is 232 °C. Reduce by about 25 °F for a convection oven.
37.8 °C. That is a hot summer day outdoors. As a body temperature it is a little above the traditional 98.6 °F average but below the usual fever threshold of 100.4 °F, which is 38 °C. The math is (100 − 32) × 5/9.
Around 37 °C, the same as 98.6 °F, though healthy readings commonly range from about 36.1 to 37.2 °C (97 to 99 °F) and vary by time of day and where the reading is taken. A reading of 38 °C (100.4 °F) or higher is generally considered a fever.
At −40 degrees. Minus 40 °F is exactly minus 40 °C, the one point where the two scales meet. You can check it with the formula: (−40 − 32) × 5/9 is −72 × 5/9, which is −40. Above that point Fahrenheit numbers are always larger.
Kelvin is the scientific scale that starts at absolute zero. It is used in physics and chemistry because it never goes negative, which makes gas-law and energy calculations work. Add 273.15 to Celsius to get Kelvin, so room temperature of 20 °C is 293.15 K. Color temperature of light bulbs is also given in kelvins.
Subtract 273.15 to get Celsius, then multiply by 9/5 and add 32. For 300 K, that is 26.85 °C, which is 80.3 °F. Type the Kelvin value in the third box and the other two fill in.