Convert Kelvin to Celsius Instantly
Use this Kelvin to Celsius calculator to convert temperature from kelvin (K) to degrees Celsius (°C) accurately. Enter any valid Kelvin temperature, reverse the conversion from Celsius to Kelvin, calculate temperature differences, or compare Kelvin, Celsius and Fahrenheit in one place.
Convert K to °C, reverse Celsius to Kelvin, compare three major temperature scales, or calculate temperature changes.
Enter a Kelvin temperature of 0 K or above. The calculator subtracts 273.15 to produce the Celsius value.
Example: 300 K
Choose displayed precision
No multiplication required
Convert degrees Celsius to Kelvin by adding 273.15. Values below −273.15°C are rejected because they would be below absolute zero.
Example: 25°C
Choose displayed precision
Kelvin uses no degree sign
Enter a Kelvin temperature once and compare it with both Celsius and Fahrenheit.
Example: 310.15 K
Applied to all results
Calculated after Celsius
Find the change between two Kelvin readings. A temperature interval of 1 K has the same magnitude as a temperature interval of 1°C.
Initial temperature
Final temperature
Offsets cancel for differences
Temperature conversions are mathematically exact for the stated scale definitions. Real-world measurement accuracy still depends on the thermometer, sensor, calibration and measurement conditions.
Kelvin to Celsius requires subtraction of 273.15, not a changing conversion factor.
The Kelvin scale begins at absolute zero, the theoretical lower limit of thermodynamic temperature.
One kelvin of temperature change has the same magnitude as one Celsius degree of change.
Write Kelvin values as 300 K, not 300°K. Celsius values use the degree symbol: 26.85°C.
The Kelvin to Celsius conversion is one of the simplest temperature conversions because the two scales use equal-sized increments. Their difference is the location of zero. Kelvin begins at absolute zero, while the Celsius scale places 0°C at the freezing point of water under specified reference conditions.
Subtract 273.15 from the Kelvin temperature. Example: 300 K − 273.15 = 26.85°C.
Because this is an offset conversion, you should not multiply Kelvin by a percentage or ratio to get Celsius. For example, 100 K is not 100°C and it is not 0°C. Instead, 100 K equals −173.15°C.
You can convert a Kelvin temperature manually in a few seconds. The process below is useful when checking calculator results or solving science and engineering problems by hand.
Start with the temperature in kelvin, such as 295 K.
This is the fixed offset between the Kelvin and Celsius zero points.
Calculate 295 − 273.15.
The result is 21.85°C.
Match your rounding to the precision of the original measurement.
Subtract 273.15 from 300. The result is 26.85°C. This is a common example because 300 K is close to a warm room temperature.
273.15 − 273.15 = 0°C. This shows the familiar offset between the scales.
250 − 273.15 = −23.15°C. A positive Kelvin value can correspond to a negative Celsius temperature because zero is located differently on the two scales.
373.15 − 273.15 = 100°C. This is the Celsius boiling point of water at standard atmospheric pressure.
The table below provides common K to °C conversions. On smaller screens the table remains inside the responsive table wrapper so it can scroll horizontally without breaking the page layout.
| Kelvin (K) | Celsius (°C) | Kelvin (K) | Celsius (°C) |
|---|---|---|---|
| 0 K | −273.15°C | 280 K | 6.85°C |
| 50 K | −223.15°C | 290 K | 16.85°C |
| 100 K | −173.15°C | 300 K | 26.85°C |
| 150 K | −123.15°C | 310 K | 36.85°C |
| 200 K | −73.15°C | 320 K | 46.85°C |
| 250 K | −23.15°C | 373.15 K | 100°C |
| 273.15 K | 0°C | 400 K | 126.85°C |
The kelvin is the SI base unit of thermodynamic temperature. It is especially important in physics, chemistry, engineering, astronomy, thermodynamics and other scientific fields because its zero corresponds to absolute zero rather than to a particular everyday reference point.
The unit name is written kelvin and its symbol is K. Unlike Celsius and Fahrenheit, Kelvin does not use a degree sign. For example, write 298.15 K, not 298.15°K.
Kelvin is useful in equations involving thermodynamic temperature because an absolute scale avoids many problems caused by arbitrary zero points. Ratios of thermodynamic temperatures are meaningful in ways that ratios of Celsius values generally are not.
The Celsius scale is widely used for weather, indoor temperatures, cooking, science communication and everyday measurement in many countries. The size of one Celsius degree is equal to the size of one kelvin, but the scales are offset by 273.15 units.
A temperature of 0°C corresponds to 273.15 K, while 100°C corresponds to 373.15 K. Because the interval size is identical, a temperature rise from 20°C to 30°C is a rise of 10°C and also a rise of 10 K.
Kelvin and Celsius are closely related but serve somewhat different purposes. Celsius is convenient for everyday temperature descriptions, while Kelvin is the standard thermodynamic temperature scale used throughout much of science.
| Feature | Kelvin | Celsius |
|---|---|---|
| Symbol | K | °C |
| Zero point | Absolute zero | 273.15 K above absolute zero |
| Degree sign | No | Yes |
| Interval size | 1 K | 1°C |
| Common use | Science and thermodynamics | Weather and everyday temperature |
| Conversion | K = °C + 273.15 | °C = K − 273.15 |
The number 273.15 is the offset between the zero points of the Kelvin and Celsius scales. Absolute zero is 0 K, corresponding to −273.15°C. Therefore, a Celsius temperature is obtained by shifting the Kelvin value downward by 273.15.
This fixed offset explains why converting a temperature difference is different from converting an absolute temperature. For absolute temperatures, you must add or subtract 273.15. For a difference, the offset cancels out. A 15 K increase is exactly a 15°C increase.
Absolute zero is 0 K, equal to −273.15°C. It represents the lower limit of thermodynamic temperature. That is why this calculator prevents users from entering a Kelvin value below zero.
Negative Celsius temperatures are perfectly valid and common, but a thermodynamic temperature below 0 K is outside the normal definition used by this converter. Likewise, the reverse calculator rejects Celsius values below −273.15°C because adding 273.15 would produce a negative Kelvin temperature.
Scientists and engineers often move between Kelvin and Celsius depending on the context. A laboratory instrument may report a temperature in Celsius, while a thermodynamic equation may require Kelvin. Because the relationship is simple, conversion errors usually come from forgetting the 273.15 offset or incorrectly using a degree symbol with Kelvin.
When a formula uses absolute temperature—such as many gas-law or thermodynamic calculations—do not substitute a Celsius number directly unless the formula specifically allows it. For example, 25°C is not numerically interchangeable with 25 K. Twenty-five degrees Celsius equals 298.15 K.
If your work also involves metric mass or length units, you can use related internal tools such as the Grams to Kilograms converter, Centimeters to Meters converter, or a broader unit converter.
One of the most useful facts about Kelvin and Celsius is that their unit intervals are the same size. If a sample warms from 280 K to 300 K, the temperature change is 20 K. In Celsius, those same endpoints are 6.85°C and 26.85°C, also a change of 20°C.
The 273.15 offset disappears when one temperature is subtracted from another.
This is why engineers may describe a temperature difference as 10 K even when the actual temperature readings are shown in degrees Celsius.
For quick mental estimates, it helps to remember a few anchor points:
| Kelvin | Celsius | Kelvin | Celsius | Kelvin | Celsius |
|---|---|---|---|---|---|
| 260 K | −13.15°C | 285 K | 11.85°C | 315 K | 41.85°C |
| 265 K | −8.15°C | 290 K | 16.85°C | 320 K | 46.85°C |
| 270 K | −3.15°C | 295 K | 21.85°C | 325 K | 51.85°C |
| 275 K | 1.85°C | 300 K | 26.85°C | 330 K | 56.85°C |
| 280 K | 6.85°C | 305 K | 31.85°C | 350 K | 76.85°C |
The mathematical conversion itself is exact because it uses the defined scale offset of 273.15. However, the accuracy of a real-world temperature reading depends on the instrument that produced the input. If a thermometer is accurate only to ±0.5°C, displaying ten decimal places after conversion does not make the physical measurement more accurate.
Use the decimal-place selector to present a sensible result. Two decimals are useful for many reference calculations. Whole degrees may be adequate for casual weather-scale comparisons, while laboratory work should follow the uncertainty and significant-figure rules required by the measurement method.
Use these related conversion pages when working with temperature or other common measurement units.
For formal definitions of the kelvin and SI temperature units, refer to recognized measurement organizations. The Bureau International des Poids et Mesures (BIPM) publishes the SI base-unit framework, while the National Institute of Standards and Technology (NIST) provides SI temperature guidance and unit information.
External references open in a new tab. This page is intended as a conversion and educational resource.
The two scales use equal-size intervals but start from different zero points.
Common questions about converting Kelvin, Celsius and temperature differences.