K = °C + 273.15
| Celsius (°C) | Kelvin (K) |
|---|---|
| -273.15 | 0 |
| -200 | 73.15 |
| -100 | 173.15 |
| -50 | 223.15 |
| -40 | 233.15 |
| -20 | 253.15 |
| 0 | 273.15 |
| 10 | 283.15 |
| 20 | 293.15 |
| 25 | 298.15 |
| 30 | 303.15 |
| 37 | 310.15 |
| 50 | 323.15 |
| 100 | 373.15 |
| 150 | 423.15 |
| 200 | 473.15 |
| 500 | 773.15 |
| 1000 | 1273.15 |
| 5000 | 5273.15 |
| 5500 | 5773.15 |
To convert Celsius to Kelvin, simply add 273.15 to the Celsius temperature. The formula is: K = °C + 273.15.
K = °C + 273.15
Convert 25°C (standard lab temperature) to Kelvin: 25 + 273.15 = 298.15 K
Convert −78.5°C (dry ice temperature) to Kelvin: −78.5 + 273.15 = 194.65 K
To convert Kelvin to Celsius, subtract 273.15: °C = K − 273.15.
\u2022 0 K (−273.15°C) is absolute zero — the theoretical lowest temperature where all molecular motion stops.
\u2022 77 K (−196°C) is the boiling point of liquid nitrogen.
\u2022 273.15 K (0°C) is the freezing point of water.
\u2022 5778 K (5505°C) is the surface temperature of the Sun.
The Kelvin scale is the SI (International System of Units) standard for temperature measurement in science and engineering. Unlike Celsius and Fahrenheit, the Kelvin scale starts at absolute zero — the point where all thermal motion ceases.
Converting Celsius to Kelvin is the easiest temperature conversion: just add 273.15. There’s no multiplication or division involved. The two scales have the same "degree size" — a 1-degree change in Celsius equals a 1-degree change in Kelvin. They differ only in their zero point.
Scientists use Kelvin because it’s an absolute scale — 0 K truly means zero thermal energy. This is crucial for gas law calculations (PV = nRT uses Kelvin), thermodynamic equations, and any physics involving temperature ratios. Saying "the temperature doubled" only makes physical sense in Kelvin: 200 K to 400 K is genuinely twice as hot, while 20°C to 40°C is not.
Liquid helium boils at 4.2 K (−269°C). Liquid nitrogen boils at 77 K (−196°C). Standard temperature and pressure (STP) is 273.15 K (0°C). Room temperature in labs is typically 293-298 K (20-25°C). These reference points come up constantly in chemistry and physics.
Add 273.15 to the Celsius temperature. For example, 100°C = 100 + 273.15 = 373.15 K.
0°C equals 273.15 K. This is the freezing point of water.
Absolute zero is 0 K (−273.15°C). It’s the theoretical lowest temperature, where all molecular motion would stop. It has never been achieved in practice.
No. Kelvin is written without the degree symbol: 300 K, not 300°K. This convention was adopted in 1967 because Kelvin is an absolute scale, not a relative one.
Kelvin is an absolute scale starting at absolute zero, which is necessary for many scientific calculations. Gas laws, thermodynamic equations, and radiation formulas all require absolute temperature.