Temperature Converter
Convert Celsius, Fahrenheit, Kelvin, Rankine, and a few historical scales.
Temperature Converter8 Scales
Convert between Celsius, Fahrenheit, Kelvin, and 5 other temperature scales with precision
Common Temperature References
Reference temperatures for everyday understanding
Physics
Science
Reference
Daily Life
Biology
Cooking
Safety
Materials
Main scales
Celsius (°C)
Water freezes at 0°C and boils at 100°C at 1 atm. Default for most countries and science labs.
Fahrenheit (°F)
Freeze 32°F, boil 212°F. Still common for weather and cooking in the US.
Kelvin (K)
SI absolute scale. 0 K is absolute zero (−273.15°C). Use for thermodynamics and gas laws.
Rankine is absolute Fahrenheit. Réaumur, Newton, Delisle, and Rømer are mostly historical; keep them for old texts, not daily work.
Conversion formulas
- °F = (°C × 9/5) + 32
- °C = (°F − 32) × 5/9
- K = °C + 273.15
- °R = °F + 459.67
Temperature is not a pure ratio conversion. Forgetting the offset is the usual bug (especially °C ↔ °F).
Related Conversion Tools
Frequently Asked Questions
Why so many scales?
Different eras and jobs picked different zero points. Celsius tracks water; Fahrenheit was tuned for weather; Kelvin starts at absolute zero for science.
Who uses Fahrenheit vs Celsius?
Most of the world uses Celsius. The US and a few others use Fahrenheit for daily weather. Science uses Celsius and Kelvin everywhere.
When should I use Kelvin?
Use Kelvin when absolute temperature or temperature ratios matter (ideal gas law, blackbody formulas). For weather and cooking, Celsius is enough.
How precise should conversions be?
Cooking and weather: whole degrees or one decimal. Lab work: match your instrument. Do not invent extra decimals the measurement never had.
Heat vs temperature?
Temperature is average particle kinetic energy. Heat is energy transferred. A lake can hold more heat than a hot mug even if the mug is hotter.
Can Kelvin be negative?
Not in ordinary thermodynamics. 0 K is absolute zero. (Specialized "negative temperature" talk in some physics contexts is a different definition.)
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