Temperature Converter
Convert between Celsius, Fahrenheit and Kelvin instantly. Type in any field to update the others.
- °C → °F: multiply by 1.8 and add 32. So 20°C = 68°F and 37°C = 98.6°F.
- °F → °C: subtract 32, then multiply by 5/9. So 100°F = 37.8°C.
- °C → K: add 273.15. Water freezes at 0°C (273.15 K) and boils at 100°C (373.15 K).
- 180°C = 356°F — a moderate oven (gas mark 4); a fan oven runs ~20°C lower.
- −40°C = −40°F, the one point where the scales meet; absolute zero is 0 K = −273.15°C.
How do you convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 (1.8) and add 32 — so 20°C is 20 × 1.8 + 32 = 68°F. To reverse it, subtract 32 from the Fahrenheit value and multiply by 5/9: 68°F is (68 − 32) × 5/9 = 20°C. The reason the formula has both a multiply and an add is that the two scales have different zero points (0°C is 32°F) and different degree sizes (1°C equals 1.8°F).
| Celsius | Fahrenheit | Everyday reference |
|---|---|---|
| 0°C | 32°F | Water freezes |
| 20°C | 68°F | Room temperature |
| 37°C | 98.6°F | Body temperature |
| 100°C | 212°F | Water boils |
What is 180°C in Fahrenheit for oven cooking?
180°C is 356°F, the standard "moderate" oven setting most UK recipes assume. It is usually labelled gas mark 4 and rounded to 350°F in American recipes. If you have a fan (convection) oven, set it about 20°C lower than a recipe's conventional temperature — so 160°C fan is roughly equivalent to 180°C conventional — because the circulating air cooks faster. The converter above turns any oven temperature between the scales instantly.
| Conventional °C | Fahrenheit | Gas mark |
|---|---|---|
| 140°C | 284°F | Gas mark 1 |
| 180°C | 356°F | Gas mark 4 |
| 200°C | 392°F | Gas mark 6 |
| 220°C | 428°F | Gas mark 7 |
Why do scientists use Kelvin instead of Celsius?
Kelvin starts at absolute zero — the coldest temperature physically possible — and never goes negative, which makes physics equations like the gas laws far simpler. A Kelvin degree is exactly the same size as a Celsius degree, so you convert simply by adding 273.15: 0°C is 273.15 K and 100°C is 373.15 K. Absolute zero itself is 0 K, or −273.15°C (−459.67°F), where molecular motion is at its minimum.
One quirk worth knowing: Celsius and Fahrenheit read the same at exactly −40°, the only crossover point between the two scales. For a named worked example you can check against the tool, type 180 into the Celsius field and the converter returns 356°F and 453.15 K — the moderate-oven figures used throughout this page. To scale a recipe up or down in quantity, use the volume converter or the percentage calculator.
Temperature conversion FAQs
Multiply the Celsius value by 9/5 (1.8) and add 32. So 20°C = 20 × 1.8 + 32 = 68°F, and 37°C = 98.6°F. To go the other way, subtract 32 from the Fahrenheit value and multiply by 5/9.
180°C equals 356°F (180 × 1.8 + 32). In oven terms 180°C is the standard "moderate" setting, often labelled gas mark 4 and rounded to 350°F in recipes. A fan oven is usually set about 20°C lower, so 160°C fan is roughly 180°C conventional.
Normal body temperature is about 37°C, which is 98.6°F (310.15 K). A fever is generally considered to start at 38°C (100.4°F). Body temperature varies by up to about half a degree through the day, so 36.5–37.5°C is all considered normal.
Absolute zero is 0 Kelvin, which equals −273.15°C or −459.67°F. It is the lowest possible temperature, where molecular motion reaches its minimum. Kelvin has no negative values, which is why scientists use it.
Celsius and Fahrenheit meet at −40°: −40°C is exactly −40°F. This is the only point where the two scales give the same number, because they rise at different rates (1°C = 1.8°F) but cross once below freezing.
Kelvin starts at absolute zero and never goes negative, so it makes physics equations — especially gas laws and thermodynamics — far simpler. A Kelvin degree is the same size as a Celsius degree, so you convert by adding 273.15 to Celsius. 0°C = 273.15 K and 100°C = 373.15 K.
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