Temperature Converter: °C, °F & Kelvin
Type in any one of the three boxes — Celsius, Fahrenheit or Kelvin — and the other two update instantly.
Convert Temperature
Quick Reference Points
Tip: type 100 into the Fahrenheit box to see the classic answer, 37.78°C.
Conversion Formulas
K = °C + 273.15 · °C = K − 273.15
Unlike most units, temperature scales start at different zero points, which is why their formulas add or subtract an offset instead of only multiplying. Celsius and Kelvin use the same step size, so converting between them is a simple shift of 273.15.
Common Temperatures Reference Table
| Reference Point | Celsius | Fahrenheit | Kelvin |
|---|---|---|---|
| Absolute zero | −273.15°C | −459.67°F | 0 K |
| Scales meet | −40°C | −40°F | 233.15 K |
| Water freezes | 0°C | 32°F | 273.15 K |
| Room temperature | 20°C | 68°F | 293.15 K |
| Body temperature | 37°C | 98.6°F | 310.15 K |
| Water boils (sea level) | 100°C | 212°F | 373.15 K |
| Moderate oven | 180°C | 356°F | 453.15 K |
About the Three Scales
The United States uses Fahrenheit for weather, cooking and body temperature, while most of the world uses Celsius. Kelvin appears in science and engineering because it starts at absolute zero — the point where molecular motion stops — making calculations cleaner. Boiling and freezing points shown here are for pure water at sea-level pressure; at high altitude, water boils a little cooler.
Frequently Asked Questions
How do I convert Fahrenheit to Celsius?
Subtract 32 from the Fahrenheit temperature, then multiply by 5/9. For example, 100°F: (100 − 32) × 5/9 = 37.78°C.
What is 100 degrees Fahrenheit in Celsius?
100°F is 37.78°C — slightly above normal human body temperature (37°C / 98.6°F), so it would count as a mild fever.
At what temperature are Fahrenheit and Celsius equal?
The two scales cross at −40: −40°F is exactly −40°C. It is the only temperature with the same value on both scales.
What is Kelvin used for?
Kelvin is the base unit of temperature in science. It starts at absolute zero (0 K = −273.15°C), the coldest temperature possible. Kelvin values never use a degree symbol — you write 300 K, not 300°K.
What is a normal body temperature in Fahrenheit and Celsius?
The commonly quoted average is 98.6°F, which is 37°C. In practice a healthy range is roughly 97–99°F (36.1–37.2°C), and readings vary by person and time of day.