Temperature Converter

Convert temperature values between Celsius (°C), Fahrenheit (°F), and Kelvin (K) instantly.

Conversion Result

Quick Conversion Table
Celsius (°C) Fahrenheit (°F) Kelvin (K) Common Reference
-273.15 -459.67 0 Absolute Zero
-40 -40 233.15 Equal Celsius and Fahrenheit
0 32 273.15 Freezing Point of Water
21 69.8 294.15 Room Temperature
37 98.6 310.15 Normal Human Body Temperature
100 212 373.15 Boiling Point of Water
Temperature Conversion Formulas
Celsius to Fahrenheit

°F = (°C × 9/5) + 32

Fahrenheit to Celsius

°C = (°F - 32) × 5/9

Celsius to Kelvin

K = °C + 273.15

Kelvin to Celsius

°C = K - 273.15

Fahrenheit to Kelvin

K = (°F - 32) × 5/9 + 273.15

Kelvin to Fahrenheit

°F = (K - 273.15) × 9/5 + 32

About Temperature Scales
Celsius (°C)

The Celsius scale, also known as the centigrade scale, is a temperature scale used by the International System of Units (SI). It was named after the Swedish astronomer Anders Celsius (1701–1744).

  • 0°C is the freezing point of water
  • 100°C is the boiling point of water (at standard atmospheric pressure)
Fahrenheit (°F)

The Fahrenheit scale is a temperature scale based on one proposed in 1724 by the physicist Daniel Gabriel Fahrenheit (1686–1736). It is used primarily in the United States.

  • 32°F is the freezing point of water
  • 212°F is the boiling point of water (at standard atmospheric pressure)
Kelvin (K)

The Kelvin scale is an absolute temperature scale used in scientific work. It was named after the Belfast-born physicist and engineer William Thomson, 1st Baron Kelvin (1824–1907).

  • 0K is absolute zero (-273.15°C), the theoretical lowest temperature possible
  • No degree symbol is used with Kelvin temperatures
  • The size of one Kelvin is the same as one degree Celsius
Temperature Conversion Tips
Quick Approximations

For a rough Celsius to Fahrenheit conversion:

  1. Double the Celsius temperature
  2. Subtract 10% of this value
  3. Add 32

Example: 20°C → 2×20 = 40 → 40-4 = 36 → 36+32 = 68°F (actual: 68°F)

Interesting Facts
  • -40 is the only temperature where Celsius equals Fahrenheit
  • The Kelvin scale has no negative temperatures
  • The Celsius scale was originally defined the opposite way (0° for boiling, 100° for freezing) before being reversed in 1743
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