What is the formula for Fahrenheit to Celsius?

To convert Fahrenheit to Celsius, use the formula: °C = (°F − 32) × 5/9. For example, 68°F = (68 − 32) × 5/9 = 20°C.

How do you convert Celsius to Kelvin?

To convert Celsius to Kelvin, add 273.15 to the Celsius value: K = °C + 273.15. For example, 0°C = 273.15K.

Temperature Converter

Convert temperatures instantly between Celsius, Fahrenheit and Kelvin. Real-time bidirectional conversion with formulas and reference table. Pure client-side.

Celsius °C

Fahrenheit °F

Kelvin K

Formula

°F = (°C × 9/5) + 32 °C = (°F − 32) × 5/9 K = °C + 273.15 °C = K − 273.15

Common Temperatures

Label	°C	°F	K
Absolute Zero	−273.15	−459.67	0
Water Freezing Point	0	32	273.15
Room Temperature	20	68	293.15
Human Body Temperature	37	98.6	310.15
Water Boiling Point	100	212	373.15

About Temperature Converter

A free, instant online tool to convert temperatures between Celsius, Fahrenheit, and Kelvin. Perfect for students, scientists, cooks, travelers, and anyone who needs quick temperature conversions. All calculations happen in your browser — no data is sent to any server.

Features

Real-time bidirectional conversion between Celsius, Fahrenheit, and Kelvin
One-click quick presets for common temperatures
Interactive reference table with absolute zero, freezing, room, body, and boiling points
Built-in formula display for all conversion directions
Copy all converted values to clipboard with one click
Validates against absolute zero — prevents impossible temperatures
100% client-side — no data sent to servers

Frequently Asked Questions

How do I convert Celsius to Fahrenheit?

Use the formula °F = (°C × 9/5) + 32. For example, 20°C = (20 × 9/5) + 32 = 68°F. You can also just enter 20 in the Celsius field and our tool will instantly show 68°F.

What is the difference between Celsius and Kelvin?

Celsius and Kelvin use the same scale size (1°C = 1K), but Kelvin starts at absolute zero (0K = -273.15°C). Kelvin is used in scientific calculations because it has no negative values.

What is absolute zero?

Absolute zero is the lowest possible temperature, where all molecular motion stops. It is 0 Kelvin, -273.15°C, or -459.67°F. Our tool prevents you from entering temperatures below absolute zero.

Why does water freeze at 0°C but 32°F?

The Celsius scale was designed so that water freezes at 0° and boils at 100°. The Fahrenheit scale, developed earlier, uses different reference points (32°F for freezing, 212°F for boiling) based on a brine solution and human body temperature.