Why does Kelvin start at 273.15 at 0°C?

Kelvin is an absolute scale anchored at absolute zero — the lowest theoretically possible temperature. The scientific definition of one degree Kelvin equals one degree Celsius.

Physically impossible — absolute zero (0 K) is the lower bound. The tool will let you type it, but no real-world matter goes below.

Why ((°F − 32) × 5/9) for Fahrenheit?

32 is where ice melts (0°C) on the Fahrenheit scale, and 9°F covers the same span as 5°C — so the ratio normalizes the scale.

SnapTools

Files never leave your device

Temperature Converter

Convert temperatures between Celsius, Fahrenheit, and Kelvin. Type in any field and the others update live.

Celsius (°C)

Fahrenheit (°F)

Kelvin (K)

How to use Temperature Converter

Type a number in any field.
The other two scales update instantly.

How to use Temperature Converter

Frequently asked questions

Why does Kelvin start at 273.15 at 0°C?

Negative Kelvin?

Why ((°F − 32) × 5/9) for Fahrenheit?