Kelvin to Celsius Calculator

Absolute temperature converter

Convert kelvins and degrees Celsius

Convert kelvins to degrees Celsius or Celsius to kelvins with the exact 273.15 offset and absolute-zero validation.

Result

273.15 K = 0 °C

Reference relationship273.15 K = 0 °C exactly

Formula useddegrees Celsius = kelvins − 273.15

Unit relationship

273.15 K = 0 °C exactly

KelvinsThe SI base unit of thermodynamic temperature.

Degrees CelsiusA Celsius interval has the same magnitude as one kelvin.

A temperature interval of one kelvin equals one degree Celsius, while 0 °C corresponds to exactly 273.15 K.

Worked example

Convert 300 K to °C

1
Start with the kelvin value
Use 300 K.
2
Apply the exact relationship
Subtract the exact 273.15 scale offset.
3
Write the degree Celsius unit
300 K = 26.85 °C.

Quick reference

Kelvins to Degrees Celsius conversion table

Common K values converted to °C
Kelvins (K)	Degrees Celsius (°C)
0 K	-273.15 °C
100 K	-173.15 °C
233.15 K	-40 °C
273.15 K	0 °C
293.15 K	20 °C
310.15 K	37 °C
373.15 K	100 °C
1,000 K	726.85 °C

Thermodynamic temperature

Move from absolute kelvin readings to the Celsius reference scale

Kelvin and Celsius intervals are the same size, but their zeros serve different purposes. Converting a reading requires one exact offset and respect for the physical lower boundary at 0 K.

Side-by-side guide · Thermodynamic temperature

Read absolute temperatures and intervals differently

Reading formula: °C = K − 273.15
Zero reference: 273.15 K = 0 °C
Correct symbol: K, never °K

A temperature reading
Convert 310.15 K by subtracting 273.15 to obtain 37 °C. The offset is essential because the two readings use different zeros.
A temperature interval
A change of 12 K is a change of 12 Celsius degrees. Offsets cancel when only the difference between two temperatures is being expressed.
A ratio statement
Claims such as “twice the thermodynamic temperature” require an absolute scale such as kelvin. Celsius numbers should not be used for that ratio because their zero is offset.

Move from absolute kelvin readings to the Celsius reference scale: Kelvin and Celsius intervals are the same size, but their zeros serve different purposes. Converting a reading requires one exact offset and respect for the physical lower boundary at 0 K.

Kelvin begins at absolute zero; Celsius begins elsewhere

The kelvin is the SI unit of thermodynamic temperature. NIST explains that 0 K is absolute zero and that 0 °C corresponds to exactly 273.15 K. Subtracting 273.15 therefore changes the reference point without changing the size of the interval. A reading of 300 K becomes 26.85 °C, while 273.15 K becomes exactly 0 °C.

The modern kelvin is defined through a fixed value of the Boltzmann constant, not by treating the Celsius ice point as its origin. The convenient 273.15 relationship still connects the two scales exactly for conversion. The result is a change of representation, not a claim about how a laboratory realizes or calibrates that temperature.

Read absolute temperatures and intervals differently

A temperature reading

Convert 310.15 K by subtracting 273.15 to obtain 37 °C. The offset is essential because the two readings use different zeros.

A temperature interval

A change of 12 K is a change of 12 Celsius degrees. Offsets cancel when only the difference between two temperatures is being expressed.

A ratio statement

Claims such as “twice the thermodynamic temperature” require an absolute scale such as kelvin. Celsius numbers should not be used for that ratio because their zero is offset.

Notation is part of an authoritative result

Write kelvin with the uppercase symbol K because the unit is named for a person, and do not add a degree sign.
Write degree Celsius as °C, with Celsius capitalized and a space between the numerical value and the unit symbol in running text.
Do not enter a negative kelvin value. A Celsius value below −273.15 °C would imply the same invalid region below 0 K.
Keep calibration uncertainty and sensor corrections separate from the exact arithmetic offset used by the converter.

Choose the destination scale for the audience

Scientific data may remain in kelvins for thermodynamic equations, while an operational report may be easier to read in Celsius. If the final audience uses Fahrenheit, first obtain Celsius here and then use the Celsius-to-Fahrenheit calculator, or select the direct pair in the general conversion calculator. Do not round the intermediate Celsius value if a direct conversion is available.

For a document that starts with an American Fahrenheit reading, the Fahrenheit-to-Celsius guide explains why the 32-degree offset is removed before applying the interval ratio. Weather humidity calculations belong in the dew point calculator; converting a scale alone does not determine moisture, heat flow, phase change, or human comfort.

Important limitations

The page converts absolute temperature readings rather than temperature intervals. It cannot accept values below 0 K or model pressure, phase changes, sensor calibration, or uncertainty.

Review the stated scope, calculation method, assumptions, supported inputs, and effective dates, and obtain qualified advice before using a high-stakes result.

This formula passed its registered engineering tests and is published under an explicit site-owner policy authorization. No independent expert, QA, editorial, legal, or third-party review is claimed. Verify consequential results with a qualified professional.

Thermodynamic temperature

Move from absolute kelvin readings to the Celsius reference scale

Kelvin and Celsius intervals are the same size, but their zeros serve different purposes. Converting a reading requires one exact offset and respect for the physical lower boundary at 0 K.

Side-by-side guide · Thermodynamic temperature

Read absolute temperatures and intervals differently

Reading formula: °C = K − 273.15
Zero reference: 273.15 K = 0 °C
Correct symbol: K, never °K

A temperature reading
Convert 310.15 K by subtracting 273.15 to obtain 37 °C. The offset is essential because the two readings use different zeros.
A temperature interval
A change of 12 K is a change of 12 Celsius degrees. Offsets cancel when only the difference between two temperatures is being expressed.
A ratio statement
Claims such as “twice the thermodynamic temperature” require an absolute scale such as kelvin. Celsius numbers should not be used for that ratio because their zero is offset.

Kelvin begins at absolute zero; Celsius begins elsewhere

Read absolute temperatures and intervals differently

A temperature reading

Convert 310.15 K by subtracting 273.15 to obtain 37 °C. The offset is essential because the two readings use different zeros.

A temperature interval

A change of 12 K is a change of 12 Celsius degrees. Offsets cancel when only the difference between two temperatures is being expressed.

A ratio statement

Claims such as “twice the thermodynamic temperature” require an absolute scale such as kelvin. Celsius numbers should not be used for that ratio because their zero is offset.

Notation is part of an authoritative result

Write kelvin with the uppercase symbol K because the unit is named for a person, and do not add a degree sign.
Write degree Celsius as °C, with Celsius capitalized and a space between the numerical value and the unit symbol in running text.
Do not enter a negative kelvin value. A Celsius value below −273.15 °C would imply the same invalid region below 0 K.
Keep calibration uncertainty and sensor corrections separate from the exact arithmetic offset used by the converter.