Kelvin to Celsius Converter — Science Temperature
Convert Kelvin to Celsius instantly with our free online temperature converter. Useful for physics, chemistry, astrophysics, and laboratory research.
Formula: °C = K − 273.15
K to C Conversion Table
| K | C |
|---|---|
| 0 K | −273.15°C |
| 273.15 K | 0°C |
| 373.15 K | 100°C |
Formula
°C = K − 273.15
Example: 0 K = −273.15°C
Frequently Asked Questions
Looking for the reverse? C to K Converter
About temperature conversion
Temperature conversion between Celsius, Fahrenheit, and Kelvin is the most common scientific calculation most people do in daily life — whether reading weather reports during international travel, following recipes from other countries, or working with lab data. Unlike length or weight, temperature scales have different zero points AND different degree sizes, so the math is a two-step process: scale the difference, then shift the zero. This is why you can't just multiply Celsius by 1.8 to get Fahrenheit — you also need to add 32.
How the math works
Celsius and Fahrenheit were both defined around water's freezing and boiling points but with different numbers: Celsius set 0 °C at freezing and 100 °C at boiling, while Fahrenheit placed freezing at 32 °F and boiling at 212 °F. Since the gap is 100 on one scale and 180 on the other, 1 °C = 1.8 °F. To convert: °F = (°C × 9/5) + 32. Kelvin is the scientific absolute scale — 0 K is absolute zero, and each Kelvin degree is the same size as a Celsius degree, just offset by 273.15. So °C = K − 273.15.
When you'll use this conversion
- Weather forecasts when traveling between metric and imperial countries
- Cooking and baking — oven temperatures vary by recipe origin
- Medical thermometers (fever threshold is 38 °C / 100.4 °F)
- Scientific experiments and lab reports (Kelvin preferred for calculations)
- HVAC and home climate control settings
- Industrial processes, welding, and metallurgy
A bit of history
Anders Celsius proposed his scale in 1742 but originally set 0 at boiling and 100 at freezing — the modern orientation was reversed after his death. Daniel Gabriel Fahrenheit created his scale in 1724 using a brine solution and human body temperature as reference points. Lord Kelvin proposed his absolute scale in 1848, which became the SI standard for science. Today, the triple point of water (0.01 °C) is the primary reference for all three scales.
Common mistakes
- Forgetting to add or subtract 32 when converting between Celsius and Fahrenheit
- Using Celsius × 2 + 30 as a shortcut — it's only a rough estimate, inaccurate below 0 °C or above 50 °C
- Confusing temperature differences (Δ°C) with temperature values (°C) — differences don't need the 32 offset
- Assuming negative Fahrenheit means below freezing — 0 °F is actually about −17.8 °C
Quick tips
- Quick mental math: to convert °C to °F, double and add 30 (approximation good ±3 °F between 0 and 30 °C)
- Body temperature is 37 °C = 98.6 °F — memorize this as an anchor
- Room temperature is roughly 20–22 °C or 68–72 °F
- In scientific writing, always use Kelvin for calculations involving ratios or gas laws