Temperature Converter
Temperature is the one everyday conversion that is not a simple multiplication — Fahrenheit has an offset of 32, so the formula has two steps. This temperature converter translates between Celsius, Fahrenheit and Kelvin instantly and exactly.
Whether you are decoding a US recipe (350 °F), a weather forecast or a physics problem, the answer is one field away.
Enter valid values to see the results.
Formula
The 1.8 factor comes from the degree sizes (180 Fahrenheit degrees span the same interval as 100 Celsius degrees), and the 32 offset aligns the freezing points of water. Kelvin starts at absolute zero and has no negative values.
What you need
- Enter the temperature and choose the source and target scales.
- Kelvin is used in science; it has no degree symbol and no negatives.
- For oven temperatures, round the result to the nearest 5–10 °F — ovens are not that precise.
Worked example
Practical tips
- Mental shortcut: °C to °F — double it and add 30 (exact would be ×1.8 + 32); good within a few degrees for weather.
- Memorable anchors: 0 °C = 32 °F (freezing), 100 °C = 212 °F (boiling), 37 °C = 98.6 °F (body), −40 °C = −40 °F (the crossover).
- At −40 the two scales meet — the only temperature where °C = °F.
- Kelvin and Celsius steps are identical; only the zero points differ by 273.15.
Temperature reference points
| Point | °C | °F |
|---|---|---|
| Water freezes | 0 | 32 |
| Room temperature | 20–22 | 68–72 |
| Body temperature | 37 | 98.6 |
| Water boils | 100 | 212 |
Common mistakes
- 1 Multiplying without the offset: 20 °C × 1.8 = 36, not 68 °F — the +32 is essential.
- 2 Applying the formula to temperature differences: a 10 °C rise is an 18 °F rise (no offset for deltas).
- 3 Using degrees with Kelvin: it is “300 K”, not “300 °K”.
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply by 1.8 and add 32: 25 °C × 1.8 + 32 = 77 °F.
How do I convert Fahrenheit to Celsius?
Subtract 32, then divide by 1.8: (98.6 − 32) ÷ 1.8 = 37 °C.
At what temperature are Celsius and Fahrenheit equal?
At −40: −40 °C = −40 °F. It is the only crossover point of the two scales.
What is absolute zero in each scale?
0 K = −273.15 °C = −459.67 °F — the point where molecular motion reaches its minimum.