What is the formula to convert Celsius to Fahrenheit?

Multiply the Celsius value by 9/5, then add 32: °F = (°C × 9/5) + 32. So 100 °C × 9/5 = 180, plus 32 equals 212 °F. For a quick mental estimate, double the Celsius value and add 30 — accurate to within a few degrees around room temperature.

How do I convert Fahrenheit to Celsius?

Subtract 32 from the Fahrenheit value, then multiply by 5/9: °C = (°F − 32) × 5/9. So 98.6 °F − 32 = 66.6, times 5/9 equals 37 °C. The rough mental version is to subtract 30 and halve the result.

At what temperature are Celsius and Fahrenheit equal?

At −40 degrees. It is the only point where the two scales read identically, which makes it a useful check when you want to confirm a conversion formula is being applied correctly.

Why does water boil at different temperatures?

The boiling point depends on air pressure. At sea level water boils at 100 °C, but at 2,000 m altitude it boils at about 93 °C, and in a pressure cooker it can exceed 120 °C. The converter uses the standard scale; it does not adjust for your local pressure or altitude.

When should I use Kelvin?

Use Kelvin for scientific and engineering work, where absolute temperature matters — gas laws, radiation, cryogenics, thermodynamics. It has no negative values, so ratios between temperatures are meaningful, which is not true of Celsius or Fahrenheit.

Temperature Converter

Celsius to Fahrenheit, Fahrenheit to Celsius, and Kelvin for scientific work. Temperature is the one conversion that cannot be done with a simple multiplier, because the scales have different zero points — this tool applies the correct formula in both directions.

Temperature

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