Temperature Converter

How to use this converter

Type a temperature in any of the three fields. The other two update as you type. Negative values work for Celsius and Fahrenheit.

Formulas

°F = °C × 9/5 + 32
°C = (°F − 32) × 5/9
K = °C + 273.15

Quick reference

Description	°C	°F	K
Absolute zero	−273.15	−459.67	0
Celsius = Fahrenheit	−40	−40	233.15
Water freezes	0	32	273.15
Room temperature	20	68	293.15
Body temperature	37	98.6	310.15
Water boils (sea level)	100	212	373.15
Moderate oven	180	356	453.15

Mental shortcut

For a rough °C → °F, double the Celsius value and add 30. For 20 °C: 40 + 30 = 70 °F (exact: 68 °F). It is close for everyday weather but drifts at high temperatures.

Where each scale is used

• Celsius — everyday use in almost every country, and in science.
• Fahrenheit — everyday use in the United States and a few other places.
• Kelvin — science and engineering; it starts at absolute zero, so it never goes negative.

Frequently asked questions

How do I convert Celsius to Fahrenheit?

Multiply by 9/5 (1.8) and add 32. 37 °C × 1.8 + 32 = 98.6 °F.

How do I convert Fahrenheit to Celsius?

Subtract 32 and multiply by 5/9. 212 °F − 32 = 180, × 5/9 = 100 °C.

At what temperature are Celsius and Fahrenheit equal?

At −40. −40 °C is exactly −40 °F.

Can Kelvin be negative?

No. 0 K is absolute zero (−273.15 °C), the lowest possible temperature.

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