A complete temperature conversion tool. Enter a value in any field to instantly convert between Celsius (°C), Kelvin (K), and Fahrenheit (°F).
How to Convert Celsius to Kelvin
The conversion from Celsius (°C) to Kelvin (K) is the simplest temperature conversion because the size of one degree Celsius is identical to the size of one Kelvin. The only difference is their "zero" point: Kelvin starts at absolute zero, while Celsius starts at the freezing point of water.
The Formula (Celsius to Kelvin)
To convert from Celsius to Kelvin, you simply add 273.15.
Example: Convert 100°C (the boiling point of water) to Kelvin.100 °C + 273.15 = 373.15 K
The Formula (Kelvin to Celsius)
To convert from Kelvin to Celsius, you subtract 273.15.
What is Absolute Zero?
The Kelvin scale is an "absolute" scale, meaning its zero point (0 K) is Absolute Zero. This is the theoretical temperature at which all atomic and molecular motion ceases. There is no temperature colder than 0 K, which is why the Kelvin scale has no negative numbers. Celsius and Fahrenheit are "relative" scales, as their zero points (0°C and 0°F) were set for convenience (e.g., the freezing point of water).
Key Temperature Points
| Point | Celsius (°C) | Kelvin (K) | Fahrenheit (°F) |
|---|---|---|---|
| Water Boils | 100 °C | 373.15 K | 212 °F |
| Human Body (Avg) | 37 °C | 310.15 K | 98.6 °F |
| Room Temperature | 20-25 °C | ~293-298 K | 68-77 °F |
| Water Freezes | 0 °C | 273.15 K | 32 °F |
| Absolute Zero | -273.15 °C | 0 K | -459.67 °F |
Frequently Asked Questions (FAQ)
What is the formula for Celsius (°C) to Kelvin (K)?
The formula is: Kelvin = Celsius + 273.15. (K = °C + 273.15).
What is 0 Celsius in Kelvin?
0 °C (the freezing point of water) is equal to 273.15 K.
What is 0 Kelvin in Celsius?
0 Kelvin (K) is equal to -273.15 °C. This is known as Absolute Zero.
Are Celsius and Kelvin the same?
They use the same increment (a change of 1°C is the same as a change of 1 K), but their zero points are different. The Kelvin scale starts at Absolute Zero (0 K = -273.15 °C), while the Celsius scale starts at the freezing point of water (0 °C = 273.15 K).