Unit Converters

Temperature Converter

Convert Celsius, Fahrenheit and Kelvin with the correct offset formulas.

Temperature values

Value

From

Converted value

Celsius (°C) → Fahrenheit (°F)

About this tool

Convert temperatures accurately between Celsius, Fahrenheit and Kelvin. Unlike simple length or mass conversions, temperature scales have different starting zero points, so this tool converts via Kelvin as an exact intermediate base.

How to use

Enter your temperature value in the input field.
Select your source unit (°C, °F, or K).
Select your target unit to view the converted temperature immediately.
Use Swap units to reverse the two scales without retyping the value.

Formula and methodology

Kelvin base pivot: K = °C + 273.15; °F = (°C × 9/5) + 32; °C = (°F − 32) × 5/9. Converting via Kelvin keeps Celsius, Fahrenheit and Kelvin consistent. Rankine and other scales are not included.

Worked example

20 °C (comfortable room temperature) = 68 °F = 293.15 K.

Celsius to Fahrenheit

F = C × 9/5 + 32. Water freezes at 0°C, which is 32°F, and boils at 100°C, which is 212°F.

Fahrenheit to Celsius

C = (F − 32) × 5/9. Body temperature 98.6°F is 37°C. The scales meet at −40, so −40°F is −40°C.

Celsius to Kelvin

K = C + 273.15, and C = K − 273.15. Freezing is 0°C or 273.15 K. A 20°C room is 293.15 K.

Common temperature reference points

0°C = 32°F = 273.15 K. 100°C = 212°F. 20°C = 68°F. 37°C = 98.6°F. These are the same formulas the converter uses.

Frequently asked questions

Why does temperature conversion require an offset rather than just multiplication?+

Celsius and Fahrenheit have different zero points: water freezes at 0°C but at 32°F. Converting between them requires subtracting or adding 32 before or after scaling by 9/5 (1.8).

What is absolute zero?+

Absolute zero is 0 Kelvin (-273.15°C or -459.67°F), the theoretical point where all molecular thermal motion ceases.