Why doesn't Kelvin go negative?

Kelvin is an absolute scale (0K = -273.15°C), the theoretical lowest possible temperature.

Is there a point where °C and °F match?

Yes — at -40° both scales coincide: -40°C = -40°F.

What is Kelvin used for?

Kelvin is the absolute scale used in physics and chemistry. 0 K is absolute zero (-273.15°C), and 1 K equals a 1°C interval.

🌡️ Temperature Converter

Convert Celsius, Fahrenheit and Kelvin instantly.

How it works

Type a value in the left field.
Pick the units to convert from and to.
The result updates instantly, with a full reference table below.

Key units & conversion basis

Unlike other categories, temperature uses formulas with offsets rather than simple multiplication. Four scales are supported: Celsius, Fahrenheit, Kelvin, and Rankine.

Reference point	Celsius (°C)	Fahrenheit (°F)	Kelvin (K)
Absolute zero	-273.15	-459.67	0
Water freezes	0	32	273.15
Body temperature	36.5~37	97.7~98.6	309.65~310.15
Water boils	100	212	373.15
Scales coincide	-40	-40	233.15

🧮 How the conversion is calculated

Fahrenheit formula: °F = °C × 9/5 + 32. Example: 25°C → 25 × 1.8 + 32 = 77°F. Kelvin only needs an offset: K = °C + 273.15.

🎯 When to use this

Convert Fahrenheit weather forecasts to Celsius
Convert Fahrenheit oven temperatures in recipes to Celsius
Convert Kelvin for scientific calculations
Convert Fahrenheit oven settings in US recipes to Celsius

📖 Guide: Converting Fahrenheit to Celsius — Formula & Shortcut →

Frequently Asked Questions

What is 100°F in Celsius?: Approximately 37.8°C.
Why doesn't Kelvin go negative?: Kelvin is an absolute scale (0K = -273.15°C), the theoretical lowest possible temperature.
Is there a point where °C and °F match?: Yes — at -40° both scales coincide: -40°C = -40°F.
What is Kelvin used for?: Kelvin is the absolute scale used in physics and chemistry. 0 K is absolute zero (-273.15°C), and 1 K equals a 1°C interval.