Temperature Converter
Celsius, Fahrenheit and Kelvin — convert any value instantly
About this tool
This free temperature converter instantly translates any temperature between Celsius (°C), Fahrenheit (°F), and Kelvin (K). Type a value in any field and the other two update in real time. It is the fastest way to convert oven temperatures for recipes, body temperatures for medical reference, or weather forecasts when traveling internationally.
Key reference points: water freezes at 0°C / 32°F / 273.15 K and boils at 100°C / 212°F / 373.15 K at standard sea-level pressure. Normal human body temperature is 37°C / 98.6°F. Room temperature is typically 20–22°C / 68–72°F. A hot oven runs around 200°C / 400°F. Absolute zero — the coldest possible temperature — is −273.15°C / −459.67°F / 0 K.
Celsius is used by almost every country in the world for everyday weather and cooking. The United States, along with a handful of other countries, still uses Fahrenheit for weather and informal temperature references. Kelvin is the SI base unit of temperature used in science and engineering because it starts at absolute zero, making it ideal for equations in thermodynamics, astrophysics, and chemistry where negative temperatures would complicate calculations.
Quick conversion formulas: °F to °C: subtract 32, then multiply by 5/9. °C to °F: multiply by 9/5, then add 32. °C to K: add 273.15. K to °C: subtract 273.15.
Common temperature converter questions
Frequently asked questions
How do you convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 (or 1.8) and then add 32. For example, 20°C × 1.8 = 36, plus 32 gives 68°F. To go the other way, subtract 32 from the Fahrenheit value and multiply by 5/9.
What is 100 degrees Fahrenheit in Celsius?
100°F is approximately 37.8°C. Subtract 32 to get 68, then multiply by 5/9, which gives 37.78°C. That is just above normal human body temperature of 37°C.
Is there a quick way to estimate Celsius to Fahrenheit?
Double the Celsius value and add 30. For 20°C that gives 70°F, close to the exact 68°F. The shortcut is accurate to within a few degrees across normal weather temperatures, which is enough for everyday use.
At what temperature are Celsius and Fahrenheit the same?
−40 degrees. Celsius and Fahrenheit scales cross at exactly −40°, so −40°C equals −40°F. It is the only point where the two scales give the same number.
Why do scientists use Kelvin instead of Celsius?
Kelvin starts at absolute zero, the point where all molecular motion stops, so it never uses negative values. That makes it well suited to thermodynamics and physics equations where the ratio between temperatures matters. One kelvin is the same size as one degree Celsius, so you convert by adding or subtracting 273.15.
What is a normal body temperature in Celsius and Fahrenheit?
Normal body temperature averages 37°C or 98.6°F, though healthy readings range from about 36.1°C to 37.2°C (97°F to 99°F) depending on the person, the time of day, and where the measurement is taken. A fever is generally considered 38°C or 100.4°F and above.