Temperature Converter
Fast, precise online temperature converter between Celsius (°C) and Fahrenheit (°F). Features exact formulas, bidirectional instant swapping, and zero ads.
Best solution
Default conversion: 25 °C is 77 °F; exact result: 77 °F.
Temperature reading · up to 2 decimal places
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Methodology & calculation rule
°F = (°C × 9/5) + 32
For a Celsius reading, multiply by 9/5 (1.8) and add 32. For Fahrenheit, subtract 32 and multiply by 5/9.
For a temperature reading, use °F = °C × 9/5 + 32, or °C = (°F − 32) × 5/9. Results are displayed to at most two decimal places. Negative values are allowed down to −273.15 °C or −459.67 °F (absolute zero). The calculator converts readings, not temperature changes: a change of 1 °C is a change of 1.8 °F, with no 32-degree offset. NIST temperature conversion reference.
Changing the input updates the calculator only; the worked example below it stays on the value named in this page. Swap uses the displayed, rounded result as the next input, so repeated swaps may introduce a small rounding difference. Unit conversion does not determine a diagnosis or a recommended device setting.
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Frequently Asked Questions
How do you convert Celsius to Fahrenheit?
Multiply the Celsius temperature by 9/5 (or 1.8) and add 32. For example, (25 × 1.8) + 32 = 77 °F.
How do you convert Fahrenheit to Celsius?
Subtract 32 from the Fahrenheit temperature and multiply by 5/9. For example, (77 − 32) × 5/9 = 25 °C.
At what temperature are Celsius and Fahrenheit equal?
Celsius and Fahrenheit are equal at −40 degrees (−40 °C = −40 °F).