Celsius to Kelvin Converter (°C to K)
Convert Celsius to Kelvin (°C to K). The simplest temperature conversion: just add 273.15. See results in Kelvin, Fahrenheit, and Rankine.
TEMPERATURE IN KELVIN
295.15 K
FAHRENHEIT
71.60 °F
RANKINE
531.27 °R
ABS ZERO?
✅ Above
FORMULA
22+273.15
Celsius to Kelvin — Quick Reference
| °C | K | °F | Context |
|---|---|---|---|
| -273.15°C | 0.00 K | -459.7°F | Absolute zero |
| -196°C | 77.15 K | -320.8°F | Liquid nitrogen boils |
| -78.5°C | 194.65 K | -109.3°F | Dry ice sublimes |
| -40°C | 233.15 K | -40.0°F | F = C crossover |
| 0°C | 273.15 K | 32.0°F | Water freezes |
| 20°C | 293.15 K | 68.0°F | Room temp (68°F) |
| 22°C | 295.15 K | 71.6°F | Room temp (72°F) |
| 25°C | 298.15 K | 77.0°F | Warm day (77°F) |
| 37°C | 310.15 K | 98.6°F | Body temperature |
| 100°C | 373.15 K | 212.0°F | Water boils |
| 180°C | 453.15 K | 356.0°F | Oven: baking |
| 1538°C | 1811.15 K | 2800.4°F | Iron melts |
| 5505°C | 5778.15 K | 9941.0°F | Sun's surface |
How to Convert Celsius to Kelvin
This is the simplest temperature conversion — just add 273.15:
Example: 0°C (water freezes)
= 0 + 273.15 = 273.15 K
Example: 22°C (room temperature)
= 22 + 273.15 = 295.15 K
Example: 100°C (water boils)
= 100 + 273.15 = 373.15 K
Why is it so simple? Because Celsius and Kelvin use the same degree size — a 1°C change equals a 1 K change. The only difference is the starting point: Kelvin starts at absolute zero (-273.15°C) instead of water's freezing point.
Celsius to Kelvin — Conversion Chart
| °C | K | °F | Significance |
|---|---|---|---|
| -273.15°C | 0 K | -459.67°F | Absolute zero |
| -196°C | 77.15 K | -320.8°F | Liquid nitrogen boils |
| -78.5°C | 194.65 K | -109.3°F | Dry ice sublimes |
| -40°C | 233.15 K | -40°F | °F = °C crossover |
| 0°C | 273.15 K | 32°F | Water freezes |
| 20°C | 293.15 K | 68°F | Room temperature |
| 37°C | 310.15 K | 98.6°F | Body temperature |
| 100°C | 373.15 K | 212°F | Water boils |
| 1538°C | 1811.15 K | 2800°F | Iron melts |
| 5505°C | 5778.15 K | 9941°F | Sun's surface |
Why 273.15?
In 1848, Lord Kelvin (William Thomson) proposed an absolute temperature scale starting at the point where molecular motion theoretically ceases. Through experiments with gas expansion, scientists determined that this "absolute zero" occurs at -273.15°C. Adding 273.15 to any Celsius temperature shifts the scale so that 0 represents absolute zero — the coldest possible temperature in the universe.
Why Does Science Use Kelvin?
| Reason | Explanation | Example |
|---|---|---|
| No negative values | Temperature is always ≥ 0 K | Simplifies thermodynamic equations |
| Absolute scale | 0 K = actual zero energy | Required for gas laws (PV = nRT) |
| Proportional | Doubling K = doubling thermal energy | 200 K has exactly 2× the energy of 100 K |
| SI standard | International System base unit | Used in all scientific publications |
| Same degree size | 1 K = 1°C change | Easy to convert: just add 273.15 |
US Courses That Use Kelvin
| Course | Level | Kelvin Used For |
|---|---|---|
| AP Chemistry | High school | Gas laws, thermochemistry, equilibrium |
| AP Physics | High school | Thermodynamics, thermal radiation |
| General Chemistry | College | Ideal gas law (PV = nRT), calorimetry |
| Organic Chemistry | College | Reaction kinetics, Arrhenius equation |
| Physics I & II | College | Heat transfer, entropy, blackbody radiation |
| Astronomy | College | Star temperatures, cosmic microwave background |
| Engineering Thermo | College | Carnot efficiency, Rankine cycle |
Cosmic Temperature Scale
| Object / Event | K | °C | Notes |
|---|---|---|---|
| Cosmic microwave background | 2.725 K | -270.4°C | Coldest natural temperature |
| Outer space (average) | ~3 K | -270°C | Near absolute zero |
| Pluto's surface | ~44 K | -229°C | Distant dwarf planet |
| Mars (average) | ~210 K | -63°C | Red planet |
| Earth (average) | ~288 K | 15°C | Our planet |
| Venus (surface) | ~737 K | 464°C | Hottest planet |
| Sun's surface | 5,778 K | 5,505°C | Yellow dwarf star |
| Sun's core | ~15,000,000 K | ~15,000,000°C | Nuclear fusion |
What Is Celsius?
Celsius (°C) is a temperature scale where 0°C = water's freezing point and 100°C = water's boiling point (at standard pressure). It is used by virtually every country in the world for everyday temperature, and in science when an absolute scale isn't required.
What Is Kelvin?
Kelvin (K) is the SI base unit of temperature. It starts at absolute zero (0 K = -273.15°C), the coldest possible temperature. Each kelvin equals one degree Celsius in size. Kelvin is used in science, engineering, and astronomy worldwide. Remember: no degree symbol — write "295 K" not "295°K".