Temperature Converter
Measurement
°C ↔ °F ↔ K with linked sliders.
Temperature
Non-linear scales : formulas: F = C × 9/5 + 32 · K = C + 273.15. Water freezes at 0 °C / 32 °F / 273.15 K.
Frequently asked questions
▶How do I convert Celsius to Fahrenheit?
°F equals °C times 9 by 5 plus 32. So 0 °C equals 32 °F (freezing), 100 °C equals 212 °F (boiling), and 37 °C body temperature equals 98.6 °F. To go from Fahrenheit to Celsius: °C equals (°F minus 32) times 5 by 9. For a quick mental check, double the Celsius and add 30 to get a rough Fahrenheit value.
▶What is the relation between Celsius and Kelvin?
Kelvin and Celsius use the same degree size, but Kelvin starts at absolute zero. So K equals °C plus 273.15. 0 °C equals 273.15 K, 25 °C room temperature equals 298.15 K, and absolute zero (minus 273.15 °C) equals 0 K. Kelvin is used in physics, chemistry, and astronomy because it has no negative values.
▶Why is body temperature 37 °C and not a round number?
37 °C (98.6 °F) is just an average : normal human body temperature ranges from 36.1 °C to 37.2 °C and varies through the day. The Fahrenheit scale was anchored to body temperature in the 1700s and called it 96 °F, but later recalibration shifted it to 98.6 °F. Neither scale was designed around the human body precisely.
▶What does negative temperature mean?
On the Celsius and Fahrenheit scales, negative numbers just mean colder than the zero point : minus 10 °C is colder than freezing. On the Kelvin scale you cannot go negative because 0 K is absolute zero, where all thermal motion stops. Indian winters in Delhi can hit 2 to 4 °C, while Leh can drop to minus 25 °C or lower.
▶Celsius versus Kelvin: when do I use which?
Use Celsius for everyday temperatures, weather, cooking, and most engineering. Use Kelvin when you do thermodynamic calculations (gas laws, heat transfer, spectroscopy) or describe very cold or very hot phenomena like stars (millions of K) or liquid helium (4 K). Mixing them up in formulas like PV equals nRT will give wrong answers.
▶Why does my oven use both °C and °F?
Most ovens are sold worldwide and labelled in both because recipes come from both systems. US recipes often say 350 °F (which is 177 °C); Indian and European recipes say 180 °C. If your oven is in °F but the recipe is in °C, use this calculator or remember a few anchors: 180 °C is about 350 °F, 200 °C is about 400 °F.