Temperature Converter
Convert between Celsius, Fahrenheit and Kelvin instantly.
Last updated: April 2026
Convert from:
Common temperatures:
| Unit | Amount |
|---|---|
| Celsius | — °C |
| Fahrenheit | — °F |
| Kelvin | — K |
Temperature comes up constantly in daily life — checking the weather, setting an oven, reading a fever. The unit used depends almost entirely on where you are in the world. Celsius is the global standard; Fahrenheit remains common in the US; Kelvin is reserved for science and engineering.
When do you need this?
- Travelling to the US — weather forecasts are in Fahrenheit; 75°F is a warm day (24°C), not a scorching one.
- Cooking from foreign recipes — American recipes give oven temperatures in °F; European ones use °C. 350°F = 175°C is a common baking temperature.
- Medical situations abroad — body temperature is 37°C or 98.6°F; a reading of 104°F means a high fever (40°C).
- Reading product specs — electronics and industrial equipment often list operating ranges in °C; some US-made gear uses °F.
- Science and chemistry — reactions and physical constants are expressed in Kelvin, where 0 K is absolute zero and there are no negative values.
- Climate data — historical records and climate models use Celsius internationally; comparing them to US data requires conversion.
Key temperature references
| Reference point | Celsius | Fahrenheit | Kelvin |
|---|---|---|---|
| Absolute zero | −273.15°C | −459.67°F | 0 K |
| Water freezes | 0°C | 32°F | 273.15 K |
| Room temperature | 20°C | 68°F | 293.15 K |
| Body temperature | 37°C | 98.6°F | 310.15 K |
| Water boils | 100°C | 212°F | 373.15 K |
| Oven (moderate) | 180°C | 356°F | 453.15 K |
Quick reference
- °C → °F: (°C × 9/5) + 32 · e.g. 100°C = 212°F
- °F → °C: (°F − 32) × 5/9 · e.g. 32°F = 0°C
- °C → K: °C + 273.15 · e.g. 0°C = 273.15 K
- K → °C: K − 273.15 · e.g. 300 K ≈ 26.85°C
- Rough shortcut (°C → °F): double the °C value and add 30 — good enough for weather
- Crossover point: −40° is the same in both Celsius and Fahrenheit
Understanding the units
Celsius (°C)
Celsius was defined by Swedish astronomer Anders Celsius in 1742, with 0° at the freezing point of water and 100° at boiling. It is the standard unit for everyday temperature in almost every country and is used in medicine, meteorology, and most scientific contexts.
Fahrenheit (°F)
Daniel Gabriel Fahrenheit proposed his scale in 1724. He set 32°F as the freezing point of water and 212°F as the boiling point, giving 180 degrees between them. It remains the everyday standard in the United States, and is still encountered in some industrial and culinary contexts globally.
Kelvin (K)
The Kelvin scale starts at absolute zero — the point where all thermal motion ceases. It uses the same degree size as Celsius, so a difference of 1 K equals a difference of 1°C. Kelvin has no negative values, which makes it essential for thermodynamics, astrophysics, and any calculation involving the laws of physics.
Common mistakes
- Forgetting to add 32 last — the Celsius-to-Fahrenheit formula is (× 9/5) + 32, not × 9/5 alone. Missing the +32 gives a result that is always too low.
- Using the wrong shortcut for body temperature — 37°C is 98.6°F, not 99°F. The difference matters clinically.
- Treating Kelvin like Celsius — 300 K is not 300°C. Subtract 273.15 to get the Celsius equivalent (26.85°C).
- Oven temperature errors — confusing °C and °F in a recipe is common. 400°F (205°C) is a hot oven; 400°C (752°F) would destroy most food.
- Assuming UK = Fahrenheit — the UK switched to Celsius officially in 1965. Older British recipes may still use °F, but modern ones use °C.
Which should you use?
Daily life outside the US: Celsius. Weather, medicine, cooking — all use °C as the default.
Daily life in the US: Fahrenheit for weather and body temperature; °C increasingly appears in cooking and science.
Science and engineering: Kelvin. Any formula involving absolute temperature (gas laws, radiation, thermodynamics) requires K.
Cooking: Use whatever the recipe specifies. Most modern recipes outside the US are in °C; American recipes are in °F.
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5, then add 32. So 20°C × 9/5 + 32 = 68°F. To go the other way, subtract 32 and multiply by 5/9.
What is 37 degrees Celsius in Fahrenheit?
37°C equals 98.6°F. This is normal human body temperature, used clinically in both units depending on the country.
At what temperature are Celsius and Fahrenheit the same?
Celsius and Fahrenheit are equal at −40 degrees. It is the only point where both scales give exactly the same reading.
What is absolute zero in Celsius and Fahrenheit?
Absolute zero is −273.15°C or −459.67°F. In the Kelvin scale it is defined as 0 K — the theoretical lowest possible temperature, where all molecular motion stops.
What countries use Fahrenheit?
The United States uses Fahrenheit for everyday temperature. Most other countries, including the UK, Australia, and all of Europe, use Celsius. Kelvin is used internationally in science and engineering.
How do I convert Fahrenheit to Kelvin?
First convert Fahrenheit to Celsius: subtract 32 and multiply by 5/9. Then add 273.15 to get Kelvin. For example, 32°F = 0°C = 273.15 K.
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