Temperature Converter
Celsius, Fahrenheit and Kelvin readings for ovens, weather, fevers and lab work
Celsius, Fahrenheit and Kelvin readings for ovens, weather, fevers and lab work. No data leaves your browser – every conversion happens locally.
Readings versus differences
This converter handles temperature readings: what a thermometer, oven dial or weather app shows. It applies the offset formulas, so 0°C becomes 32°F and 0 K becomes −273.15°C.
Temperature changes are different. A rise of 10°C is a rise of 18°F, not 50°F, because the 32-degree offset cancels out. If you're converting a difference (say, "the room warmed by 5°C"), multiply by 1.8 instead of using the tool.
Celsius, Fahrenheit and Kelvin are covered. Rankine, used in a few US engineering fields, isn't.
How temperature conversion actually works
It's not just multiplication
Unlike length or weight, Celsius and Fahrenheit have different zero points. The formula is °F = (°C × 9/5) + 32. Going the other way: °C = (°F − 32) × 5/9.
Key reference points
Water freezes at 0°C / 32°F. Body temperature is 37°C / 98.6°F. A hot summer day is 35°C / 95°F. Oven temperatures: 180°C = 356°F, 200°C = 392°F.
Kelvin is just Celsius shifted
0 K = −273.15°C (absolute zero). Room temperature (~20°C) = 293.15 K. Kelvin is used in physics and chemistry, not everyday life.
Worked examples
Oven settings
180°C is 356°F, so most US recipes round it to 350°F. 220°C is 428°F, usually written as 425°F.
Fever check
38.5°C is 101.3°F. Most doctors treat anything from 38°C (100.4°F) upwards as a fever.
Freezer temperature
The usual −18°C setting is −0.4°F, which is why US manuals just say 0°F.
Temperatures worth knowing in all three scales
These are the readings people look up most: freezer, fridge, room, body and oven temperatures. Fahrenheit is °C × 1.8 + 32, and Kelvin is °C + 273.15.
| Celsius | Fahrenheit | Kelvin | What it is |
|---|---|---|---|
| −40°C | −40°F | 233.15 K | Where both scales meet |
| −18°C | −0.4°F | 255.15 K | Home freezer |
| 0°C | 32°F | 273.15 K | Water freezes |
| 4°C | 39.2°F | 277.15 K | Fridge |
| 20°C | 68°F | 293.15 K | Room temperature |
| 37°C | 98.6°F | 310.15 K | Normal body temperature |
| 100°C | 212°F | 373.15 K | Water boils at sea level |
| 180°C | 356°F | 453.15 K | Moderate oven |
| 220°C | 428°F | 493.15 K | Hot oven |
Why quick temperature shortcuts drift
The "double it and add 30" shortcut is exact only at 10°C. At 30°C it gives 90°F against a true 86°F, and at 40°C it's 6°F too high. That's fine for a weather forecast and not fine for a fever reading or sugar work, where a few degrees matter.
Oven settings trip people up for a different reason. Many UK recipes give a lower figure for fan ovens, often 20°C below the conventional temperature, so check which one the recipe means before you convert. And Kelvin has no degree sign: it's 300 K, not 300°K, since a 1967 change to the SI.