What are zero and one hundred Celsius in Fahrenheit?

Convert Celsius to Fahrenheit by multiplying by 9/5 and adding 32. Accordingly, 0 Celsius equals 32 Fahrenheit, and 100 Celsius equals 212 Fahrenheit. The scales have different zero points, so a simple multiplication alone is insufficient for temperature values. Distinguish a measured temperature from a temperature difference, since a difference uses only the scale ratio and does not include the same additive offset.

Why do I subtract 273.15 when converting kelvin to Celsius?

Kelvin and Celsius have equal-sized degree intervals but zero points separated by 273.15. A temperature of 0 Celsius equals 273.15 kelvin, so subtracting 273.15 converts a kelvin value to Celsius. Check which temperature scale a physical formula expects before inserting the result. A formula requiring absolute temperature cannot necessarily use a Celsius value directly, even though a change of one unit has the same size on both scales.

How many Fahrenheit degrees correspond to a ten-degree Celsius difference?

A difference of 10 Celsius degrees equals a difference of 18 Fahrenheit degrees, without adding the 32-degree zero-point offset. This page converts temperature values, so a temperature difference should not be entered as though it were an absolute reading. For a heating change or experimental difference, use the scale ratio alone. Applying the ordinary temperature formula to that difference would introduce an offset that does not belong there.

Temperature converter

Convert between Celsius, Fahrenheit, Kelvin, Rankine and Réaumur

Computed in your browser

Pick the scales at both ends to see the result. Temperature scales have a zero offset, so they cannot be converted by a single multiplication.

Value

Unit of the value

Target unit

Common conversions

Significant digits

This affects display only. Conversion always uses full precision.

Every unit at once
Unit	Symbol	Result
Celsius	°C
Fahrenheit	°F
Kelvin	K
Rankine	°R
Réaumur	°Ré

Example

Input

25 °C

Example result

°F   77
K    298.15
°R   536.67
°Ré  20

Because of the zero offset, temperature cannot be converted by a single multiplication the way length can.

Technical details & limits

Temperature scales are related affinely rather than proportionally. A value is first taken to kelvin by multiplying by a scale factor and adding an offset, then taken back out to the target scale. Fahrenheit and Rankine use a factor of 5/9; Réaumur uses 5/4.

About this tool

Temperature does not scale proportionally: a conversion has to handle both the size of a degree and where zero sits. Enter a value, pick its scale, and the page returns Celsius, Fahrenheit, Kelvin, Rankine and Réaumur using each scale’s defined relation to the kelvin.

Use cases

Convert Fahrenheit in a forecast or an oven manual into Celsius.
Turn Celsius in lab notes into kelvin.
Read temperatures recorded in Réaumur in older sources.

How to use

Type a number. Decimals and scientific notation such as 1.5e3 are accepted.
Pick the unit the value is in and the unit you want it in. The ⇄ button swaps the two.
The summary line gives the target scale; the table below lists all five scales at the same time.
Adjust the significant digits for a shorter or longer number. The conversion itself always runs at full precision.

Notes

The page converts between scales and does not judge whether a result is physically possible. Entering a value below absolute zero produces a negative kelvin figure, which is not blocked.

FAQ

What are zero and one hundred Celsius in Fahrenheit?: Convert Celsius to Fahrenheit by multiplying by 9/5 and adding 32. Accordingly, 0 Celsius equals 32 Fahrenheit, and 100 Celsius equals 212 Fahrenheit. The scales have different zero points, so a simple multiplication alone is insufficient for temperature values. Distinguish a measured temperature from a temperature difference, since a difference uses only the scale ratio and does not include the same additive offset.
Why do I subtract 273.15 when converting kelvin to Celsius?: Kelvin and Celsius have equal-sized degree intervals but zero points separated by 273.15. A temperature of 0 Celsius equals 273.15 kelvin, so subtracting 273.15 converts a kelvin value to Celsius. Check which temperature scale a physical formula expects before inserting the result. A formula requiring absolute temperature cannot necessarily use a Celsius value directly, even though a change of one unit has the same size on both scales.
How many Fahrenheit degrees correspond to a ten-degree Celsius difference?: A difference of 10 Celsius degrees equals a difference of 18 Fahrenheit degrees, without adding the 32-degree zero-point offset. This page converts temperature values, so a temperature difference should not be entered as though it were an absolute reading. For a heating change or experimental difference, use the scale ratio alone. Applying the ordinary temperature formula to that difference would introduce an offset that does not belong there.

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