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Temperature Conversion.

Convert between Fahrenheit, Celsius, Kelvin, and Rankine temperature scales with precise results.

Convert between Fahrenheit, Celsius, Kelvin, and Rankine. Temperature conversions use formulas rather than simple multipliers, so these calculators handle the math for you with precise results.

Popular Conversions

Celsius to Fahrenheit Celsius to Kelvin Fahrenheit to Celsius Kelvin to Celsius
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Temperature scale conversions

Unlike most unit conversions, temperature requires both multiplication and addition. The formula from Celsius to Fahrenheit is F = (C x 9/5) + 32. For Kelvin, add 273.15 to Celsius. Two handy reference points: water freezes at 0°C (32°F) and boils at 100°C (212°F). The scales cross at -40, where -40°C equals -40°F.

Common questions about temperature conversions

How do I convert Fahrenheit to Celsius?

Subtract 32, then multiply by 5/9. For example, 72°F minus 32 is 40, and 40 times 5/9 equals 22.2°C. For a rough mental estimate, subtract 30 and divide by 2. That gives you 21°C for 72°F, which is close enough for everyday use.

What is Kelvin used for?

Kelvin is the SI unit of temperature, used in science and engineering. It starts at absolute zero (0 K = -273.15°C), the point where molecular motion theoretically stops. Room temperature (about 20°C) is 293.15 K. Kelvin uses the same degree size as Celsius, so a 1°C change equals a 1 K change.

What is absolute zero?

Absolute zero is 0 Kelvin, -273.15°C, or -459.67°F. It's the lowest possible temperature, where atoms have minimal vibrational motion. Scientists have cooled materials to within billionths of a degree above absolute zero, but reaching it exactly is considered physically impossible.