Switch Tool
Everyday Essentials
Engineering & Data
13 tools — all free & precise
Temperature
Temperature Converter
Convert Celsius, Fahrenheit, and Kelvin
Conversion Formula
C → F: (C × 9/5) + 32 | F → C: (F − 32) × 5/9 | C → K: C + 273.15
Temperature conversions require nonlinear equations rather than simple ratios:
Celsius to Fahrenheit: (°C × 9/5) + 32 = °F
Fahrenheit to Celsius: (°F − 32) × 5/9 = °C
Celsius to Kelvin: °C + 273.15 = K
Kelvin to Celsius: K − 273.15 = °C
Fahrenheit to Kelvin: (°F − 32) × 5/9 + 273.15 = K
Temperature conversion is unique because it does not use simple ratios — the scales have different zero points. Water freezes at 0°C (32°F, 273.15 K) and boils at 100°C (212°F, 373.15 K).
Our converter handles all linear and nonlinear temperature conversions between Celsius, Fahrenheit, and Kelvin instantly.
All Supported Temperature Units
| Unit | Symbol | Definition |
|---|---|---|
| Celsius | °C | The metric temperature scale where water freezes at 0° and boils at 100°. |
| Fahrenheit | °F | The imperial temperature scale where water freezes at 32° and boils at 212°. |
| Kelvin | K | The SI base unit of thermodynamic temperature, starting at absolute zero. |
| Rankine | °R | The absolute Fahrenheit scale used in some engineering fields. |
Temperature Reference Points
| Reference | Conversion |
|---|---|
| Absolute Zero | −273.15°C |
| −459.67°F | 0 K |
| Water Freezes | 0°C / 32°F / 273.15 K |
| Room Temp | ~21°C / ~70°F / ~294 K |
| Body Temp | 37°C / 98.6°F / 310.15 K |
| Water Boils | 100°C / 212°F / 373.15 K |
Frequently Asked Questions
To convert Celsius to Fahrenheit, multiply by 9/5 and add 32. For example, 30°C × (9/5) + 32 = 86°F. This is the most common temperature conversion query.
The 9/5 factor accounts for the different scale sizes (180°F between freezing and boiling vs 100°C). The 32 accounts for the different zero points.
No. Kelvin is an absolute temperature scale where 0 K is absolute zero — the coldest possible temperature. Kelvin values are always non-negative.
Celsius is based on water freezing at 0° and boiling at 100°. Fahrenheit has water freezing at 32° and boiling at 212°. Celsius is used in most countries; Fahrenheit is primarily used in the US.
To convert Fahrenheit to Celsius, subtract 32 and multiply by 5/9. For example, (98.6°F − 32) × 5/9 = 37°C (normal body temperature).
Absolute zero is 0 K, which equals −273.15°C and −459.67°F. At this temperature, all molecular motion theoretically stops.
To convert Kelvin to Celsius, subtract 273.15. For example, 300 K − 273.15 = 26.85°C. Kelvin is the SI base unit for thermodynamic temperature.