Temperature conversion trips up travelers, cooks, scientists, and students alike. This guide covers all the formulas and shows how to convert between any temperature scales instantly.
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Convert Temperature →Temperature Scales Explained
| Scale | Freezing Point | Boiling Point | Used In |
|---|---|---|---|
| Celsius (°C) | 0°C | 100°C | Most of the world |
| Fahrenheit (°F) | 32°F | 212°F | USA, some Caribbean |
| Kelvin (K) | 273.15 K | 373.15 K | Science |
| Rankine (°R) | 491.67 °R | 671.67 °R | Engineering (US) |
Conversion Formulas
# Celsius ↔ Fahrenheit
°F = (°C × 9/5) + 32
°C = (°F − 32) × 5/9
# Celsius ↔ Kelvin
K = °C + 273.15
°C = K − 273.15
# Fahrenheit ↔ Kelvin
K = (°F + 459.67) × 5/9Common Reference Points
| Reference | °C | °F | K |
|---|---|---|---|
| Absolute zero | −273.15 | −459.67 | 0 |
| Water freezes | 0 | 32 | 273.15 |
| Human body | 37 | 98.6 | 310.15 |
| Water boils | 100 | 212 | 373.15 |
| Sun's surface | 5,500 | 9,932 | 5,773 |
Frequently Asked Questions
Is there a quick mental trick for C to F?
Double the Celsius, subtract 10%, add 32. For 20°C: 40 − 4 + 32 = 68°F (exact: 68°F). Close enough for weather!
What temperature is the same in Celsius and Fahrenheit?
−40°. At −40, both scales give the same reading: −40°C = −40°F.
What is absolute zero?
The coldest possible temperature: 0 Kelvin = −273.15°C = −459.67°F. At absolute zero, particles have minimum possible energy.
Why does the US still use Fahrenheit?
Historical inertia. The US, Myanmar, and Liberia are the only countries that haven't officially switched to the metric system, which uses Celsius.