🌡️ Temperature Converter
By ToolNimba Editorial Team · Updated 2026-06-19
Type a value in any box and the others convert instantly.
Convert between Celsius, Fahrenheit and Kelvin in one place. Type a value into any field below and the other two scales update instantly, so you can go from Celsius to Fahrenheit, Fahrenheit to Celsius or Celsius to Kelvin without reaching for a calculator. The exact formulas and a quick-reference chart sit just below the tool.
What is the Temperature Converter?
Three temperature scales cover almost everything you will run into. Celsius (C) is the everyday metric scale used by most of the world: it pins 0 to the freezing point of water and 100 to its boiling point at sea level, which makes it easy to reason about weather and cooking. Fahrenheit (F) is the scale used mainly in the United States, where water freezes at 32 and boils at 212, giving 180 degrees between the two fixed points instead of 100. Kelvin (K) is the scientific (SI) scale: it uses the same size step as Celsius but starts from absolute zero rather than the freezing point of water, so there are no negative values.
Absolute zero is the coldest temperature physically possible, the point where molecular motion is at its minimum. It sits at 0 K, which is -273.15 C and -459.67 F. Because Kelvin counts up from that floor, converting Celsius to Kelvin is just a shift: add 273.15. There is no multiplication because a one-degree change in Celsius is exactly a one-kelvin change.
The formulas differ because the scales disagree on two things: where zero sits and how big one degree is. Celsius and Kelvin share a degree size, so they differ only by an offset (273.15). Celsius and Fahrenheit share neither, so converting between them needs both a scale factor (9/5, because 180 Fahrenheit degrees span the same range as 100 Celsius degrees) and an offset (32, because Fahrenheit places water freezing at 32 rather than 0).
When to use it
- Reading a weather forecast or recipe written in the other unit while travelling.
- Setting an oven from a recipe that lists Fahrenheit when your dial is in Celsius.
- Converting a body-temperature reading between scales to check for a fever.
- Doing science or engineering homework that requires Kelvin for gas-law calculations.
How to use the Temperature Converter
- Type a number into the Celsius, Fahrenheit or Kelvin field.
- The other two scales update automatically as you type.
- Read off the converted values, or copy the result you need.
Formula & method
Worked examples
Convert normal body temperature, 37 °C, to Fahrenheit.
- Multiply by 9/5: 37 × 9/5 = 66.6
- Add 32: 66.6 + 32 = 98.6
Result: 37 °C = 98.6 °F
Convert 100 °C (boiling water) to Fahrenheit.
- Multiply by 9/5: 100 × 9/5 = 180
- Add 32: 180 + 32 = 212
Result: 100 °C = 212 °F
A recipe says 350 °F. Convert that oven temperature to Celsius.
- Subtract 32: 350 − 32 = 318
- Multiply by 5/9: 318 × 5/9 = 176.67
Result: 350 °F ≈ 177 °C
Common temperatures in Celsius and Fahrenheit
| Reference point | Celsius | Fahrenheit |
|---|---|---|
| Absolute zero | -273.15 °C | -459.67 °F |
| Water freezes | 0 °C | 32 °F |
| Cold winter day | -18 °C | 0 °F |
| Room temperature | 21 °C | 70 °F |
| Body temperature | 37 °C | 98.6 °F |
| Water boils (sea level) | 100 °C | 212 °F |
Common oven temperatures (Fahrenheit to Celsius, rounded)
| Oven description | Fahrenheit | Celsius |
|---|---|---|
| Slow / low | 325 °F | 163 °C |
| Moderate | 350 °F | 177 °C |
| Moderately hot | 375 °F | 191 °C |
| Hot | 400 °F | 204 °C |
| Hot | 425 °F | 218 °C |
| Very hot | 450 °F | 232 °C |
Common mistakes to avoid
- Forgetting the +32 offset. When converting Celsius to Fahrenheit, multiplying by 9/5 alone is not enough. You must add 32 afterwards, otherwise every answer comes out far too low.
- Subtracting 32 in the wrong order. Going from Fahrenheit to Celsius, subtract 32 first, then multiply by 5/9. Multiplying before subtracting gives the wrong result.
- Adding 273 instead of 273.15. For everyday work the rounding is harmless, but for precise science use the full 273.15 when converting Celsius to Kelvin.
- Writing degrees with Kelvin. Kelvin values are written as "300 K", not "300 °K". Kelvin is not a degree scale, so it takes no degree symbol.
Glossary
- Celsius
- The metric temperature scale where water freezes at 0 and boils at 100 at sea level. Also called centigrade.
- Fahrenheit
- The scale used mainly in the United States, where water freezes at 32 and boils at 212.
- Kelvin
- The SI temperature scale, with the same degree size as Celsius but starting from absolute zero, so 0 K = -273.15 °C.
- Absolute zero
- The lowest possible temperature, where molecular motion is minimal: 0 K, -273.15 °C, or -459.67 °F.
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 (which is 1.8) and then add 32. For example, 20 °C × 9/5 = 36, and 36 + 32 = 68 °F.
How do I convert Fahrenheit to Celsius?
Subtract 32 from the Fahrenheit value first, then multiply the result by 5/9. For example, (68 − 32) × 5/9 = 36 × 5/9 = 20 °C.
What is 37 degrees Celsius in Fahrenheit?
37 °C equals 98.6 °F, the figure usually quoted as normal human body temperature. The maths is 37 × 9/5 + 32 = 98.6.
Is Celsius or Fahrenheit bigger?
A single Fahrenheit degree is smaller than a single Celsius degree, because there are 180 Fahrenheit degrees between water freezing and boiling versus 100 Celsius degrees. So one Celsius degree equals 1.8 Fahrenheit degrees. The two scales read the same number only at -40.
How do I convert Celsius to Kelvin?
Add 273.15 to the Celsius value. For example, 25 °C + 273.15 = 298.15 K. There is no multiplication because Celsius and Kelvin use the same size degree.
What temperature is the same in Celsius and Fahrenheit?
Minus 40 degrees. At -40, the two scales meet exactly, so -40 °C = -40 °F. It is the only point where the readings are identical.