Temperature Converter
Enter a temperature, choose whether it is in Celsius, Fahrenheit or Kelvin, and read it in all three scales at once. The formulas are shown below, with worked examples for cooking, weather and body temperature.
Last updated November 2, 2026
Result
20°C = 68°F = 293.15 K
| Scale | Temperature |
|---|---|
| Celsius (°C) | 20°C |
| Fahrenheit (°F) | 68°F |
| Kelvin (K) | 293.15 K |
°F = °C × 9/5 + 32 and K = °C + 273.15. Results are rounded to 2 decimal places.
Show the work
Formula: °F = °C x 9 / 5 + 32; °C = (°F - 32) x 5 / 9; K = °C + 273.15
- Entered: 20°C.
- Celsius is the starting point, so no first conversion is needed.
- Fahrenheit: 20 x 9 / 5 + 32 = 68°F.
- Kelvin: 20 + 273.15 = 293.15 K.
Result: 20°C = 68°F = 293.15 K
How to convert Celsius, Fahrenheit and Kelvin
°F = °C × 9/5 + 32 · °C = (°F − 32) × 5/9 · K = °C + 273.15
Celsius and Fahrenheit place zero in different spots and use degrees of different size. Water freezes at 0 °C and 32 °F and boils at 100 °C and 212 °F at sea level, so 100 Celsius degrees span the same range as 180 Fahrenheit degrees. A Fahrenheit degree is therefore 5/9 of a Celsius degree, which is why the conversion multiplies by 9/5 and then adds the 32 degree offset.
Kelvin uses the same size of degree as Celsius but starts at absolute zero, so converting between them only shifts the number by 273.15. A temperature in kelvins is written without a degree sign: 20 °C is 293.15 K. To go from Fahrenheit to Kelvin, convert to Celsius first and then add 273.15.
See how we calculate for the formulas, sources and review schedule behind every calculator.
Also useful alongside this calculator: Pace Calculator, MPG Calculator and Percentage Calculator.
Absolute zero and the limits of the scales
Absolute zero is the coldest temperature that can exist, where particles have no thermal motion left to lose. It is 0 K, which is −273.15 °C or −459.67 °F. Because nothing can be colder, this converter rejects any value below it instead of returning a meaningless number.
There is no matching upper limit. Temperatures inside stars reach millions of kelvins, so a very large entry is accepted and converted with the same three formulas.
The point where Celsius and Fahrenheit agree
The two scales show the same number at exactly −40. Setting °F = °C in the formula gives C = C × 9/5 + 32, which solves to C = −40. So −40 °C is −40 °F, and it is a handy check that a conversion went the right way.
Between 0 and 100 °C the Fahrenheit reading is always larger than the Celsius one, and below −40 it is the other way round.
Quick estimates without a calculator
To estimate Fahrenheit from Celsius, double the Celsius value and add 30. For 20 °C that gives 70 °F, close to the exact 68 °F. To go back, subtract 30 from the Fahrenheit value and halve it: 70 °F gives 20 °C. The shortcut is within about 2 degrees for everyday weather and drifts for very hot or cold values.
For cooking, memorize a few anchors instead. 180 °C is 356 °F, usually written as 350 °F in recipes, and 200 °C is 392 °F, usually written as 400 °F. Oven dials and recipes round these numbers, so a small difference is normal.
Where each scale is used
Most of the world uses Celsius for weather, cooking and body temperature, while the United States uses Fahrenheit for the same things. Science and engineering use kelvins because they start at absolute zero, which keeps gas laws and radiation formulas simple. Fahrenheit is also used on US oven dials and by US weather services.
Normal body temperature is about 37 °C, which is 98.6 °F, and a fever is usually counted from about 38 °C or 100.4 °F. The converter does not give medical advice, so use it only to translate a reading from one scale to another.
How to use the Temperature Converter
- Enter the temperature as a number. Negative values are allowed.
- Choose the scale it is in: Celsius, Fahrenheit or Kelvin.
- Read the result in all three scales, then use Copy, Print or Share.
Worked example
To convert 350 °F to Celsius, subtract 32 to get 318, multiply by 5 to get 1,590 and divide by 9. The result is about 176.67 °C, which is 449.82 K. Going the other way, 20 °C times 9/5 is 36, and adding 32 gives 68 °F, which is 293.15 K. In each case the conversion is the same two arithmetic steps, so the result can be checked by running them in reverse.
| Reference point | °C | °F | K |
|---|---|---|---|
| Absolute zero | −273.15 | −459.67 | 0 |
| Water freezes | 0 | 32 | 273.15 |
| Room temperature | 20 | 68 | 293.15 |
| Normal body temperature | 37 | 98.6 | 310.15 |
| Water boils (sea level) | 100 | 212 | 373.15 |
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 (1.8) and add 32. For example, 25 °C × 1.8 = 45, plus 32 gives 77 °F.
How do I convert Fahrenheit to Celsius?
Subtract 32 and multiply by 5/9. For example, 68 °F minus 32 is 36, times 5/9 gives 20 °C.
How do I convert Celsius to Kelvin?
Add 273.15 to the Celsius value. 0 °C is 273.15 K, and 100 °C is 373.15 K. Kelvin is written without a degree sign.
Is there a temperature below absolute zero?
No. Absolute zero is 0 K, −273.15 °C or −459.67 °F, and the converter shows an error for anything colder.
Are my numbers stored anywhere?
No. The conversion runs in your browser, and nothing you enter is saved or uploaded unless you choose to share a link.