Temperature Converter
-40° is where Celsius and Fahrenheit finally agree. A rare moment of harmony.
Celsius (°C)
100°C
Fahrenheit (°F)
212°F
F = (C × 9/5) + 32
Kelvin (K)
373.15K
K = C + 273.15
Notable Temperatures
About This Calculator
How It Works
Unlike most unit conversions, temperature doesn't convert by simple multiplication — it requires both scaling and offsetting because the zero points of Celsius, Fahrenheit, and Kelvin are all different. Celsius and Kelvin share the same scale (a 1°C change = a 1K change), but Kelvin starts at absolute zero while Celsius starts at the freezing point of water. Fahrenheit uses a different scale altogether. This calculator handles all three directions and shows the formula being applied.
The Formula
F = (C × 9/5) + 32. C = (F - 32) × 5/9. K = C + 273.15. Absolute zero = -273.15°C = -459.67°F = 0K.
When to Use This
Temperature conversion is one of those things that comes up constantly across cooking (oven temperatures), weather (understanding forecasts from another country), science (converting experimental results), and travel (reading a thermostat in a country that uses a different scale). Knowing that 100°C is boiling, 37°C is body temperature, and 20°C is a comfortable room — those reference points make the conversions intuitive.
Example
Body temperature: 98.6°F = 37°C = 310.15K. Room temperature: 72°F = 22.2°C = 295.4K. Now you can sound smart in any unit.
Did You Know?
-40° is the one magical temperature where the Celsius and Fahrenheit scales intersect. At exactly -40, both scales read the same number. It's the only thing they agree on. Symbolic, really.