The formulas
- °F = °C × 9/5 + 32
- °C = (°F − 32) × 5/9
- K = °C + 273.15 (Kelvin has no degree symbol — it's an absolute scale)
Reference points worth remembering
| Point | °C | °F | K |
|---|---|---|---|
| Absolute zero | −273.15 | −459.67 | 0 |
| Water freezes | 0 | 32 | 273.15 |
| Room temp (approx) | 21–22 | 70–72 | 294–295 |
| Body temp | 37 | 98.6 | 310.15 |
| Water boils | 100 | 212 | 373.15 |
Fun fact: −40 is the same in Celsius and Fahrenheit (−40°C = −40°F) — the only point where the two scales cross.