Free online Celsius to Fahrenheit calculator

Celsius and Fahrenheit are two ways to measure temperature. This calculator converts between them (and Kelvin) instantly.

Celsius

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°C

Fahrenheit

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°F

Kelvin

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Common reference points

Point	°C	°F	K

How to use

Celsius → Fahrenheit: F = C × 9/5 + 32

Fahrenheit → Celsius: C = (F − 32) × 5/9

Celsius → Kelvin: K = C + 273.15

Kelvin → Celsius: C = K − 273.15

Temperature	°C	°F	K
Absolute zero	−273.15	−459.67	0
Water freezes	0	32	273.15
Room temperature	20	68	293.15
Body temperature	37	98.6	310.15
Water boils	100	212	373.15

Source: NIST temperature definitions and SI unit standards.
Results are rounded to 4 decimal places to avoid floating-point noise.
The Kelvin scale has no negative values — temperatures below 0 K are physically impossible.

How do you convert Celsius to Fahrenheit?

F = C × 9/5 + 32. Example: 100°C = 100 × 1.8 + 32 = 212°F (boiling point of water).

How do you convert Fahrenheit to Celsius?

C = (F − 32) × 5/9. Example: 98.6°F = (98.6 − 32) × 5/9 = 37°C (normal body temperature).

How do you convert Celsius to Kelvin?

K = C + 273.15. Kelvin uses the same scale increment as Celsius but starts at absolute zero (−273.15°C). Example: 0°C = 273.15 K.

At what temperature are Celsius and Fahrenheit equal?

−40°. At −40°C = −40°F, the two scales intersect. This is because the offset (32) and scale factor (9/5) produce the same value at that point.

What is absolute zero in all three scales?

Absolute zero is 0 K = −273.15°C = −459.67°F. It is the theoretical temperature at which all thermal motion ceases.