Tool
Temperature Converter
Type any value — Celsius, Fahrenheit, or Kelvin — and all three update instantly.
Celsius
°C
Fahrenheit
°F
Kelvin
K
Common temperatures
Convert temperatures in three steps
Works in any browser, on any device. No install required.
Enter a temperature
Type any temperature value in the input field.
Choose your units
Convert between Celsius, Fahrenheit, and Kelvin.
See all conversions at once
All three values update simultaneously so you can pick the one you need.
Temperature scales
Celsius, Fahrenheit, Kelvin
Convert between all three scales in one place. Type in any one field.
All values update live
Change one and all three update instantly. No submit button.
Formula shown
See the conversion formula used so you can repeat the math yourself.
About the Temperature Converter
Three temperature scales exist, and they each measure the same thing — thermal energy — but start and scale differently. Knowing which one you're in matters when reading a weather forecast, following a recipe, or doing a physics problem.
Celsius is the global standard. Water freezes at 0°C and boils at 100°C. It's what weather apps, cooking recipes, and thermostats use almost everywhere outside the United States.
Fahrenheit is used primarily in the US. Water freezes at 32°F and boils at 212°F. If a US weather app says 95°F, that's 35°C — a hot day.
Kelvin is the scientific standard. It uses the same step size as Celsius but starts at absolute zero — the coldest possible temperature, −273.15°C. There are no negative Kelvin values. Scientists use it because equations like the ideal gas law require an absolute scale with no negatives.
Converting between them is just arithmetic. Celsius to Fahrenheit: multiply by 9/5, then add 32. Fahrenheit to Celsius: subtract 32, then multiply by 5/9. Celsius to Kelvin: add 273.15. This converter does the math as you type.
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Frequently Asked Questions
What is the formula for Celsius to Fahrenheit?
°F = (°C × 9/5) + 32. A quick shortcut: double the Celsius, subtract 10%, then add 32. For example: 20°C → 40 - 4 + 32 = 68°F (actual: 68°F exactly).
What is absolute zero in Celsius and Fahrenheit?
Absolute zero is 0 Kelvin = -273.15°C = -459.67°F. It's the theoretical minimum temperature where all thermal motion stops. Nothing in nature reaches absolute zero.
When would I need Kelvin?
Kelvin is used in science and engineering — particularly in physics, chemistry, and astrophysics. Weather and cooking use Celsius or Fahrenheit. Kelvin appears in calculations involving gas laws, blackbody radiation, and color temperature in photography/video.
Is body temperature really 98.6°F / 37°C?
That figure dates to a 19th century German study. Modern research suggests average healthy temperature is closer to 97.5°F / 36.4°C, with normal ranging from 97°F to 99°F (36.1°C to 37.2°C).