OTHER · TEMPERATURE CONVERTER
Temperature Converter Calculator
Convert between Celsius, Fahrenheit, and Kelvin instantly. Enter one temperature and see all three scales simultaneously. Uses exact affine transforms — not ratios.
About This Calculator
Enter any temperature in Celsius, Fahrenheit, or Kelvin and see all three scales at once. Uses exact affine transforms (°C = (°F − 32) × 5/9, K = °C + 273.15) — the only correct method, since temperature scales differ by both slope and offset.
How It Works
Choose an input scale, enter a value, and the calculator converts to the other two simultaneously. The conversion goes through a canonical Celsius intermediate. Values below absolute zero (−273.15°C / 0 K) are rejected.
The Formula
°F → °C: C = (F − 32) × 5/9. °C → °F: F = C × 9/5 + 32. °C ↔ K: K = C + 273.15. These are affine transforms, not ratios — converting 0°C is NOT 0°F.
Frequently Asked Questions
- What is absolute zero?
- Absolute zero is 0 K = −273.15°C = −459.67°F — the lowest possible temperature, where all thermal motion ceases. Values below this are physically impossible.
- Why is −40°C equal to −40°F?
- The Celsius and Fahrenheit scales cross at −40°. This is the only point where both scales give the same number, because the scales differ by both a slope factor (9/5) and an offset (32).
- Why is temperature conversion not just multiplication?
- Unlike length or weight, temperature scales have different zero points. 0°C (water's freezing point) is 32°F — not 0°F. Multiplying without the offset gives wrong results.