Temperature Converter — Celsius to Fahrenheit & More
Convert temperatures between Celsius, Fahrenheit, Kelvin, and Rankine instantly.
🔄 Unit Converters
✅ Free
By SwiftCalcTools Editorial Team · Formula verified
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How to Use Temperature Converter
- 1Enter the required values in the input fields above.
- 2Click the Calculate button or results update instantly as you type.
- 3View your results in the output panel below the inputs.
- 4Adjust any values to recalculate instantly.
Frequently Asked Questions
Formula: °F = (°C × 9/5) + 32. Quick trick: double the Celsius value, subtract 10%, add 32. Example: 30°C → 30×2=60, -6=54, +32=86°F. Exact: 30×9/5+32 = 54+32 = 86°F. To go the other way: °C = (°F − 32) × 5/9.
Absolute zero (0 Kelvin = −273.15°C = −459.67°F) is the coldest theoretically possible temperature. At absolute zero, molecular motion would essentially stop. It has never been reached in practice — scientists have gotten to within nanokelvins. The Kelvin and Rankine scales start at absolute zero.
Both start at absolute zero but use different degree sizes. Kelvin uses Celsius-sized degrees: K = °C + 273.15. Rankine uses Fahrenheit-sized degrees: °R = °F + 459.67. Kelvin is used globally in science. Rankine was historically used in US engineering thermodynamics (steam tables, etc.) but has largely been replaced by Kelvin.
−40°. At −40°C = −40°F, both scales give the same reading. This is the only temperature where the two are equal. Formula: set °F = °C → C = C×9/5 + 32 → solve: −4/5 × C = 32 → C = −40.