Temperature Converter
Convert °C, °F and K with exact formulas — no factor tables needed because temperature scales are linear functions, not multiples.
| Reference point | °C | °F | K |
|---|---|---|---|
| Absolute zero | −273.15 | −459.67 | 0 |
| Water freezes | 0 | 32 | 273.15 |
| Body temperature | 37 | 98.6 | 310.15 |
| Water boils | 100 | 212 | 373.15 |
How to use
- Type a temperature and pick the from/to scale.
- The result updates live — formulas run instantly.
- Hit ⇅ to swap scales and invert the conversion.
Frequently asked questions
How do Celsius and Fahrenheit relate?
Fahrenheit = Celsius × 9/5 + 32. The two scales agree at −40 degrees, and the Fahrenheit degree is 5/9 the size of a Celsius degree. Water freezes at 0 °C / 32 °F and boils at 100 °C / 212 °F at sea level.
What is Kelvin used for?
Kelvin is the SI base unit of thermodynamic temperature, used in science and engineering. It starts at absolute zero (0 K = −273.15 °C), the point where molecular motion is minimal. Kelvin uses the same degree size as Celsius but has no degree symbol.
Why can temperatures be negative but Kelvin cannot?
Celsius and Fahrenheit are relative scales anchored to water’s properties, so they go negative. Kelvin measures from absolute zero — the coldest possible temperature — so nothing can be colder than 0 K.
Is the −40° crossover a coincidence?
It is a mathematical certainty: solving C = C × 9/5 + 32 gives exactly −40. Any two linear scales that differ in offset and step size cross at exactly one point, and for these two it happens to be −40.
Which temperature should I use for cooking?
Recipes state their own scale, so convert as needed: 180 °C ≈ 356 °F is a common oven setting, and a comfortable room sits near 21 °C / 70 °F. The converter handles exact values — ovens are approximate by nature.