Temperature Converter Online

Celsius, Fahrenheit, and Kelvin are used in different contexts — Celsius for everyday weather and cooking, Fahrenheit in the US, Kelvin in scientific work. Converting between them involves formulas rather than simple multiplication, which makes a tool like this genuinely useful.

How it works

Enter a temperature value, select your source scale, and the tool applies the exact conversion formula client-side:

• °C to °F: multiply by 9/5, then add 32
• °F to °C: subtract 32, then multiply by 5/9
• °C to K: add 273.15

How to use it

1. Enter your temperature value
2. Select the source scale (Celsius, Fahrenheit, or Kelvin)
3. Read the equivalent values in all other scales instantly

Supported scales

Celsius (°C), Fahrenheit (°F), Kelvin (K), and Rankine (°R).

A few things worth knowing

• Kelvin has no degree symbol: It's written as 300 K, not 300°K. Kelvin is an absolute scale — 0 K is absolute zero, the coldest possible temperature
• Absolute zero: 0 K = -273.15°C = -459.67°F — the theoretical point at which all molecular motion stops
• Body temperature: 37°C = 98.6°F = 310.15 K
• Water boils at: 100°C = 212°F = 373.15 K (at sea level)

FAQ

Why does converting Fahrenheit to Celsius require two steps? Because the two scales have different zero points and different step sizes. Celsius and Kelvin have the same step size (just different zeros), so those convert with a single addition.

What is Rankine? Rankine is an absolute temperature scale based on Fahrenheit degrees. It's used in some US engineering contexts. 0°R = absolute zero; water freezes at 491.67°R.

Is -40° the same in both Celsius and Fahrenheit? Yes — -40°C = -40°F exactly. It's the one point where both scales agree.

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