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Temperature Converter

Convert between Celsius, Fahrenheit and Kelvin instantly — enter a value and see the temperature in all three units.

Temperature

From unit

Celsius

100 °C

Fahrenheit

212 °F

Kelvin

373.15 K

What is a temperature converter?

A temperature converter switches a value between the three main temperature scales — Celsius, Fahrenheit and Kelvin — and shows the same temperature across them all at once. Celsius is the everyday metric scale based on water boiling at 100 degrees and freezing at zero. Fahrenheit is used mainly in the United States, with water freezing at 32 and boiling at 212 degrees. Kelvin is the scientific scale that starts at absolute zero, the coldest possible temperature, and is used in physics, chemistry and engineering. Because the scales have different zero points and different increments, converting between them needs a formula, but it works both ways. This tool updates all three units live as you type, so you can read the Celsius, Fahrenheit and Kelvin values in one place. It is handy for cooking, weather reports, travel, science coursework and lab work, and everything runs privately in your browser.

Example

Enter 100 degrees Celsius and the tool shows the same temperature as 212 °F and 373.15 K — the boiling point of water on each scale.

Who is this temperature converter for?

This free temperature converter is built for anyone who needs to make a conversion quickly, but a few groups reach for it most often.

Students and young adults: Science classes are built on celsius, fahrenheit and kelvin. A temperature converter for students checks the equivalence without memorising formulas.
Designers and developers: Weather and IoT dashboards often display different scales; this temperature converter is a temperature converter for developers wiring them up.
Professionals: Cooks, engineers and technicians switch scales constantly and use the temperature converter to convert a reading.
Curious users: Anyone who has seen a US recipe in fahrenheit can use the temperature converter to get celsius.

Temperature equivalence table

Same three formulas the tool uses: Fahrenheit = Celsius x 9/5 + 32 and Kelvin = Celsius + 273.15.

Celsius	Fahrenheit	Kelvin
0 °C	32 °F	273.15 K
20 °C	68 °F	293.15 K
37 °C	98.6 °F	310.15 K
100 °C	212 °F	373.15 K
-40 °C	-40 °F	233.15 K

Common use cases

Converting an oven temperature from a recipe written in Celsius to Fahrenheit.
Understanding a foreign weather forecast in your own unit when travelling.
Doing science or cooking experiments that need a precise Celsius or Kelvin value.
Checking thermostat and clinical readings across different measurement systems.

Pro tips

Remember the key reference points: water freezes at 0 °C / 32 °F and boils at 100 °C / 212 °F.
-40 degrees is the one temperature where Celsius and Fahrenheit are equal.
Absolute zero is 0 K, which equals -273.15 °C, the lowest temperature physically possible.
To convert Celsius to Fahrenheit, multiply by 9/5 and add 32; to go back, subtract 32 and multiply by 5/9.

How to use

Type any temperature value.
Choose the unit it is in — Celsius, Fahrenheit or Kelvin.
The value is converted and shown in all three units instantly.

Temperature formulas

°F = °C × 9/5 + 32        K = °C + 273.15
°C = (°F − 32) × 5/9       K = (°F − 32) × 5/9 + 273.15
°C = K − 273.15            °F = (K − 273.15) × 9/5 + 32

FAQ

How do I convert celsius to fahrenheit?

Multiply the Celsius value by 9/5 and add 32. For example, 100 °C gives 100 × 9/5 + 32 = 212 °F.

How do I convert fahrenheit to celsius?

Subtract 32, then multiply by 5/9. For example, 212 °F gives (212 − 32) × 5/9 = 100 °C.

What is kelvin and how do I use it?

Kelvin is the SI unit of temperature, where 0 K is absolute zero. Convert from Celsius by adding 273.15, and subtract 273.15 to go back.

Is this temperature converter free?

Yes. It is free, runs in your browser, and no data is uploaded.

How do I convert Celsius to Fahrenheit?

Multiply the Celsius value by 9/5 and add 32. So 100 °C becomes 100 × 9/5 + 32 = 212 °F.

How do I convert Fahrenheit to Celsius?

Subtract 32 from the Fahrenheit value, then multiply by 5/9. So 212 °F becomes (212 - 32) × 5/9 = 100 °C.

What is Kelvin?

Kelvin is the SI unit of temperature, starting at absolute zero (0 K = -273.15 °C). It uses the same increment as Celsius.

How do I convert Celsius to Kelvin?

Add 273.15 to the Celsius value. For example, 25 °C is 25 + 273.15 = 298.15 K.

Is -40 the same in Celsius and Fahrenheit?

Yes. -40 °C equals -40 °F, the only point where the two scales meet.

What is absolute zero?

It is the lowest possible temperature, 0 K or -273.15 °C, where molecular motion nearly stops.