Temperature Converter
Last updated: 2026-06-25
Temperature conversion uses the formulas Fahrenheit = Celsius × 9/5 + 32 and Kelvin = Celsius + 273.15. Celsius is the base, and Fahrenheit and Kelvin are converted through Celsius.
Enter a value below and pick a unit; Celsius (°C), Fahrenheit (°F) and Kelvin (K) update instantly.
Enter a temperature
Results
| Unit | Value |
|---|
How to use
- Enter a value — Type the temperature value you want to convert. Negative numbers are allowed.
- Pick the source unit — Choose the unit of your value (Celsius, Fahrenheit or Kelvin) from the dropdown.
- Read the results — Celsius (°C), Fahrenheit (°F) and Kelvin (K) all update instantly.
Celsius to Fahrenheit formula and Kelvin
Unlike length and weight, temperature is not a simple ratio — each scale puts its zero in a different place, so it is an interval unit. That means you cannot convert it by multiplication alone; you also need addition and subtraction. This converter uses Celsius as the middle reference to move between Fahrenheit and Kelvin.
| Conversion | Formula |
|---|---|
| Celsius → Fahrenheit | °F = °C × 9/5 + 32 |
| Fahrenheit → Celsius | °C = (°F − 32) × 5/9 |
| Celsius → Kelvin | K = °C + 273.15 |
| Kelvin → Celsius | °C = K − 273.15 |
| Reference | Celsius (°C) | Fahrenheit (°F) | Kelvin (K) |
|---|---|---|---|
| Water freezes | 0 | 32 | 273.15 |
| Body temperature | 36.5 | 97.7 | 309.65 |
| Water boils | 100 | 212 | 373.15 |
| Absolute zero | -273.15 | -459.67 | 0 |
Interestingly, −40 °C and −40 °F are exactly the same. For more conversion tips, see the unit conversion cheat sheet.
Frequently asked questions (FAQ)
What is the formula to convert Celsius to Fahrenheit?
Fahrenheit (°F) = Celsius (°C) × 9/5 + 32. For example, body temperature 36.5 °C is 36.5 × 1.8 + 32 = 97.7 °F. To convert Fahrenheit back to Celsius, use (°F − 32) × 5/9.
What is 100 °F in Celsius?
100 °F is about 37.78 °C. (100 − 32) × 5/9 = 37.78, which is slightly above the normal human body temperature of 36.5 °C.
How do I convert Kelvin (K)?
Kelvin (K) = Celsius (°C) + 273.15. Absolute zero 0 K is −273.15 °C; water freezes at 0 °C = 273.15 K and boils at 100 °C = 373.15 K.
Is there a temperature where Celsius and Fahrenheit are equal?
Yes. −40 °C equals exactly −40 °F. It is the only point where the two scales cross.
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Last updated: 2026-06-25