Temperature Converter
Enter a value in any field to convert to other units.
| Description | °C | °F | K | °R |
|---|---|---|---|---|
| Absolute Zero | -273.15 | -459.67 | 0 | 0 |
| Freezing Point (Water) | 0 | 32 | 273.15 | 491.67 |
| Room Temperature | 20 | 68 | 293.15 | 527.67 |
| Body Temperature | 37 | 98.6 | 310.15 | 558.27 |
| Boiling Point (Water) | 100 | 212 | 373.15 | 671.67 |
Celsius to Fahrenheit: °F = (°C × 9/5) + 32
Fahrenheit to Celsius: °C = (°F - 32) × 5/9
Celsius to Kelvin: K = °C + 273.15
Kelvin to Celsius: °C = K - 273.15
Fahrenheit to Rankine: °R = °F + 459.67
Rankine to Fahrenheit: °F = °R - 459.67
Kelvin to Rankine: °R = K × 9/5
Rankine to Kelvin: K = °R × 5/9
About the Temperature Converter
The Temperature Converter translates a temperature reading between the three most widely used scales: Celsius, Fahrenheit, and Kelvin. You type a value on one scale and instantly see its equivalents on the others, which is handy whether you are interpreting a weather forecast, a recipe, a lab procedure, or a scientific dataset that uses an unfamiliar unit.
Unlike length or weight, temperature scales do not share a single zero point, so conversion requires both scaling and shifting. To go from Celsius to Fahrenheit you multiply by 9/5 and add 32; to reverse it you subtract 32 and multiply by 5/9. Kelvin shares the same degree size as Celsius but starts at absolute zero, so Celsius plus 273.15 gives Kelvin. These offsets are why 0 degrees Celsius equals 32 degrees Fahrenheit and 273.15 Kelvin, and why the scales cross at minus 40, where Celsius and Fahrenheit read the same number.
Common scenarios include travelers converting forecasts between Celsius and Fahrenheit, cooks adapting oven temperatures across regional recipes, students and scientists working in Kelvin for thermodynamics and gas-law problems, and anyone reading equipment specs rated in a different scale. The Kelvin scale is especially important in physics and chemistry because it is absolute, making it the correct unit for calculations involving ratios of temperature.
A useful reference set worth memorizing: water freezes at 0 C, 32 F, and 273.15 K, and boils at 100 C, 212 F, and 373.15 K at sea level. Remember that Kelvin values are never reported with a degree symbol and cannot go below zero, since absolute zero (0 K, about minus 273.15 C) is the coldest possible temperature. For everyday body-temperature checks, normal human temperature is about 37 C or 98.6 F.
Frequently asked questions
- How do I convert Celsius to Fahrenheit?
- Multiply the Celsius value by 9/5 (1.8) and add 32. For example, 20 C becomes 20 times 1.8 plus 32, which equals 68 F.
- What is the relationship between Celsius and Kelvin?
- They use the same degree size, but Kelvin starts at absolute zero. Add 273.15 to a Celsius value to get Kelvin, or subtract 273.15 from Kelvin to get Celsius.
- At what temperature do Celsius and Fahrenheit read the same?
- At minus 40 degrees. Both scales coincide there, so minus 40 C equals minus 40 F exactly.
- Why can Kelvin never be negative?
- Kelvin is an absolute scale that begins at absolute zero, the lowest theoretically possible temperature, which is about minus 273.15 C. Nothing can be colder, so Kelvin values are always zero or positive.