Temperature Converter
Convert between Celsius, Fahrenheit, Kelvin and Rankine instantly
// Visual Thermometer & Reference Points
// Conversion Steps
// Click to Convert
// All Conversion Formulas
Temperature Scales Explained
Temperature measures the average kinetic energy of particles in a substance. The four main scales differ in their zero points and degree sizes.
The Four Scales
Absolute Zero
Absolute zero (0 K / −273.15°C / −459.67°F) is the theoretical lowest possible temperature — the point at which all molecular motion stops. It has never been achieved in practice, though scientists have reached within billionths of a degree of it in laboratory conditions.
From the Blog
// Quick °C → °F
Double the Celsius, subtract 10%, then add 32. For 20°C: 40 − 4 + 32 = 68°F (exact). Works best for common temperatures.
// The −40 Point
−40°C = −40°F exactly. This is the only temperature where the two scales meet. Useful as a mental checkpoint.
// Kelvin in Science
Scientists almost always use Kelvin because it's an absolute scale — no negatives. Gas law calculations (PV = nRT) require Kelvin.
// Body Temperature
Normal body temperature is 37°C (98.6°F). A fever is typically considered > 38°C (100.4°F). Hypothermia below 35°C (95°F).