Temperature Converter: Celsius (°C), Fahrenheit (°F) & Kelvin (K)
Convert temperatures accurately across Celsius, Fahrenheit, and Kelvin. Unlike length or mass, temperature scales use different zero-point offsets as well as different step sizes—making exact affine conversion formulas essential for science, meteorology, cooking, and engineering.
Key Physical Temperature Benchmarks
| Physical Reference | Celsius (°C) | Fahrenheit (°F) | Kelvin (K) |
|---|---|---|---|
| Absolute Zero | -273.15 °C | -459.67 °F | 0 K |
| Celsius / Fahrenheit Intersection | -40 °C | -40 °F | 233.15 K |
| Water Freezing Point (1 atm) | 0 °C | 32 °F | 273.15 K |
| Standard Room Temperature | 20 °C | 68 °F | 293.15 K |
| Normal Human Body Temperature | 37 °C | 98.6 °F | 310.15 K |
| Water Boiling Point (1 atm) | 100 °C | 212 °F | 373.15 K |
1. Celsius ↔ Fahrenheit Offset Formulas
A 1 °C interval equals 1.8 °F (9/5 °F), with freezing shifted from 0 °C to 32 °F:
2. Celsius ↔ Kelvin Thermodynamic Scale
Kelvin shares the exact same unit magnitude as Celsius (1 K = 1 °C) but starts at absolute zero:
Temperature Converter FAQs
Why does Kelvin not use a degree (°) symbol?
In the International System of Units (SI), Kelvin is an absolute thermodynamic unit rather than a relative degree scale. By international convention adopted in 1967, temperatures on the Kelvin scale are written as “273.15 K” (kelvins) rather than “273.15 °K”.
At what temperature are Celsius and Fahrenheit equal?
Celsius and Fahrenheit read the exact same numerical value at -40° (-40 °C = -40 °F). Solving x = (x × 9/5) + 32 yields -4/5 x = 32, so x = -40.