How do you convert kelvin to Celsius?
Subtract 273.15. The step is identical on both scales, a change of 1 K equals 1 °C: only the origin differs, since the kelvin starts at absolute zero.
K = °C + 273.15
Reference temperatures in kelvin and Celsius
| 0 K (absolute zero) | −273.15 °C |
| 2.7 K (cosmic microwave background) | −270.45 °C |
| 77 K (liquid nitrogen) | −196.15 °C |
| 273.15 K | 0 °C |
| 293.15 K | 20 °C |
| 300 K | 26.85 °C |
| 373.15 K | 100 °C |
| 5,778 K (surface of the Sun) | 5,504.85 °C |
Show every value
- 1 K = 1 °C
- 2 K = 2 °C
- 3 K = 3 °C
- 4 K = 4 °C
- 5 K = 5 °C
- 6 K = 6 °C
- 7 K = 7 °C
- 8 K = 8 °C
- 9 K = 9 °C
- 10 K = 10 °C
- 11 K = 11 °C
- 12 K = 12 °C
- 13 K = 13 °C
- 14 K = 14 °C
- 15 K = 15 °C
- 16 K = 16 °C
- 17 K = 17 °C
- 18 K = 18 °C
- 19 K = 19 °C
- 20 K = 20 °C
- 21 K = 21 °C
- 22 K = 22 °C
- 23 K = 23 °C
- 24 K = 24 °C
- 25 K = 25 °C
- 26 K = 26 °C
- 27 K = 27 °C
- 28 K = 28 °C
- 29 K = 29 °C
- 30 K = 30 °C
- 31 K = 31 °C
- 32 K = 32 °C
- 33 K = 33 °C
- 34 K = 34 °C
- 35 K = 35 °C
- 36 K = 36 °C
- 37 K = 37 °C
- 38 K = 38 °C
- 39 K = 39 °C
- 40 K = 40 °C
- 41 K = 41 °C
- 42 K = 42 °C
- 43 K = 43 °C
- 44 K = 44 °C
- 45 K = 45 °C
- 46 K = 46 °C
- 47 K = 47 °C
- 48 K = 48 °C
- 49 K = 49 °C
- 50 K = 50 °C
- 51 K = 51 °C
- 52 K = 52 °C
- 53 K = 53 °C
- 54 K = 54 °C
- 55 K = 55 °C
- 56 K = 56 °C
- 57 K = 57 °C
- 58 K = 58 °C
- 59 K = 59 °C
- 60 K = 60 °C
- 61 K = 61 °C
- 62 K = 62 °C
- 63 K = 63 °C
- 64 K = 64 °C
- 65 K = 65 °C
- 66 K = 66 °C
- 67 K = 67 °C
- 68 K = 68 °C
- 69 K = 69 °C
- 70 K = 70 °C
- 71 K = 71 °C
- 72 K = 72 °C
- 73 K = 73 °C
- 74 K = 74 °C
- 75 K = 75 °C
- 76 K = 76 °C
- 77 K = 77 °C
- 78 K = 78 °C
- 79 K = 79 °C
- 80 K = 80 °C
- 81 K = 81 °C
- 82 K = 82 °C
- 83 K = 83 °C
- 84 K = 84 °C
- 85 K = 85 °C
- 86 K = 86 °C
- 87 K = 87 °C
- 88 K = 88 °C
- 89 K = 89 °C
- 90 K = 90 °C
- 91 K = 91 °C
- 92 K = 92 °C
- 93 K = 93 °C
- 94 K = 94 °C
- 95 K = 95 °C
- 96 K = 96 °C
- 97 K = 97 °C
- 98 K = 98 °C
- 99 K = 99 °C
- 100 K = 100 °C
- 125 K = 125 °C
- 150 K = 150 °C
- 175 K = 175 °C
- 200 K = 200 °C
- 225 K = 225 °C
- 250 K = 250 °C
- 275 K = 275 °C
- 300 K = 300 °C
- 325 K = 325 °C
- 350 K = 350 °C
- 375 K = 375 °C
- 400 K = 400 °C
- 425 K = 425 °C
- 450 K = 450 °C
- 475 K = 475 °C
- 500 K = 500 °C
- 550 K = 550 °C
- 600 K = 600 °C
- 650 K = 650 °C
- 700 K = 700 °C
- 750 K = 750 °C
- 800 K = 800 °C
- 850 K = 850 °C
- 900 K = 900 °C
- 950 K = 950 °C
- 1,000 K = 1,000 °C
- 1,500 K = 1,500 °C
- 2,000 K = 2,000 °C
- 2,500 K = 2,500 °C
- 3,000 K = 3,000 °C
- 3,500 K = 3,500 °C
- 4,000 K = 4,000 °C
- 4,500 K = 4,500 °C
- 5,000 K = 5,000 °C
- 5,500 K = 5,500 °C
- 6,000 K = 6,000 °C
- 6,500 K = 6,500 °C
- 7,000 K = 7,000 °C
- 7,500 K = 7,500 °C
- 8,000 K = 8,000 °C
- 8,500 K = 8,500 °C
- 9,000 K = 9,000 °C
- 9,500 K = 9,500 °C
- 10,000 K = 10,000 °C
Since 2019 the kelvin has been defined by fixing the Boltzmann constant at 1.380 649 × 10⁻²³ J/K. The 273.15 offset from the Celsius scale is exact by definition. Methodology & sources.
Frequently asked questions
What is 300 K in Celsius?
300 K is 26.85 °C. Physicists often use 300 K as a reference room temperature: the figure is round in kelvin and close to a real lab, which 293.15 K, exactly 20 °C, would not be.
Why are bulbs labelled 2700 K or 6500 K?
That is not the bulb's temperature but its colour temperature: the temperature a black body would need to emit that shade. 2700 K gives warm white, 6500 K a cool daylight. Converting those values to Celsius serves no practical purpose.
How cold is liquid nitrogen?
77 K, that is −196.15 °C, at atmospheric pressure. This is its boiling point: above it the nitrogen evaporates, which is why an open flask of liquid nitrogen steams continuously.
Is there a Fahrenheit equivalent of the kelvin?
Yes, the degree Rankine, still used in US thermodynamics and air conditioning work. It starts at the same absolute zero but steps like Fahrenheit: 0 K = 0 °R, and 1 K equals 1.8 °R. So 300 K is 540 °R, and you go from Fahrenheit to Rankine by adding 459.67.
Where is the coldest known place?
A laboratory, not space. The cosmic microwave background keeps the whole universe at 2.7 K, and the only natural spot found colder so far is the Boomerang Nebula at roughly 1 K, chilled by the rapid expansion of its own gas. On Earth, the dilution refrigerators that host quantum computers reach about 10 millikelvin, that is −273.14 °C, 270 times colder than the background.