Temperature Converter
Convert temperatures between Celsius, Fahrenheit, Kelvin and Rankine.
From
To
1 °C =
| Fahrenheit | 33.8 °F |
| Kelvin | 274.15 K |
| Rankine | 493.47 °R |
Examples
| Input | Result |
|---|---|
| Convert 100 C to Fahrenheit | 212 F (100 x 9/5 + 32) |
| Convert 98.6 F to Celsius | 37 C ((98.6 - 32) x 5/9) |
| Convert 25 C to Kelvin | 298.15 K (25 + 273.15) |
| Convert -40 C to Fahrenheit | -40 F (-40 x 9/5 + 32) |
About this calculator
A temperature converter switches a reading between the three scales people actually use: Celsius (degrees C), Fahrenheit (degrees F), and Kelvin (K). Celsius is the everyday metric scale across most of the world, Fahrenheit is standard in the United States, and Kelvin is the absolute scale used in science where zero represents the complete absence of thermal energy.
Unlike length or weight, temperature scales do not share a single zero point, so conversion needs both a multiplication and an addition. To go from Celsius to Fahrenheit you multiply by 9/5 and add 32. To go from Fahrenheit to Celsius you subtract 32 first, then multiply by 5/9. Kelvin is the simplest: it shares the size of the Celsius degree but starts 273.15 lower, so you simply add 273.15 to a Celsius value to get Kelvin, or subtract it to go back.
Using the tool is a matter of typing the temperature, choosing the scale you are starting from, and choosing the scale you want. The converted value appears at once, and you can switch the source and target scales freely to compare a reading in all three.
When interpreting results, lean on familiar reference points. Water freezes at 0 C, 32 F, and 273.15 K, and boils at 100 C, 212 F, and 373.15 K. Normal human body temperature is about 37 C or 98.6 F. There is also one famous crossover point: minus 40 degrees is the same number on both the Celsius and Fahrenheit scales.
The most frequent error is forgetting the offset and only multiplying or dividing, which throws every answer off by a large constant. Another is treating Kelvin like the others and writing degrees Kelvin or a degree symbol; by convention Kelvin is written as a plain number followed by K. Because Kelvin starts at absolute zero, a valid Kelvin temperature can never be negative, which is a quick way to spot a mistaken entry.
Frequently asked questions
Multiply the Celsius value by 9/5 (which is 1.8) and then add 32. For example, 20 C becomes 20 x 1.8 = 36, plus 32 equals 68 F. The reverse is to subtract 32 first, then multiply by 5/9.
They use the same size degree but a different starting point. Kelvin equals Celsius plus 273.15, so 0 C is 273.15 K and 100 C is 373.15 K. Subtract 273.15 to convert Kelvin back to Celsius.
At minus 40 degrees. Minus 40 C equals minus 40 F exactly, which is the only point where the two scales meet. It is a handy fact for checking that your conversion formula is working correctly.
Kelvin starts at absolute zero, the lowest physically possible temperature where molecular motion stops. Since there is nothing colder than 0 K, no genuine temperature reading on the Kelvin scale can fall below zero.
Water freezes at 0 C, 32 F, and 273.15 K, and boils at 100 C, 212 F, and 373.15 K at standard pressure. Normal body temperature is about 37 C, which is 98.6 F.
Did this calculator help you?