Need to convert Celsius to Kelvin (°C → K)? The converter above delivers instant results. Below: the exact formula, a reference table, real-world examples, and the history of both units — everything you need for accurate °C to K conversion.
The History of the Celsius
Anders Celsius proposed his temperature scale in 1742 — but originally with 100° as freezing and 0° as boiling. His colleague Carl Linnaeus reversed it to the intuitive modern form shortly after Celsius's death in 1744. The SI officially defines 0°C = 273.15 K, and 0°C is still (very nearly) the freezing point of pure water at standard pressure. Almost every country except the United States uses Celsius for daily weather, medicine, and cooking.
The History of the Kelvin
William Thomson (later Lord Kelvin) proposed the absolute temperature scale in 1848, derived from his work on thermodynamics and the Carnot cycle. He identified absolute zero as the temperature at which a perfect gas would have zero volume — later understood as the point of minimum molecular kinetic energy. The kelvin became the SI base unit for temperature in 1954. It's mandatory for all thermodynamic calculations: the ideal gas law (PV = nRT), Stefan-Boltzmann radiation law, and Planck's blackbody formula all require temperatures in kelvin.
How to Convert Celsius to Kelvin
Add 273.15.
K = °C + 273.15Step-by-Step Example
- Take your Celsius value — for example, 25 °C.
- Apply the formula: Add 273.15.
- Result: 298.15 K.
Pro Tip: For quick °C to K conversions without arithmetic, bookmark this page. The interactive tool above updates instantly as you type.
Celsius to Kelvin Reference Table
| Celsius (°C) | Kelvin (K) |
|---|---|
| -40 °C | 233.15 K |
| -20 °C | 253.15 K |
| 0 °C | 273.15 K |
| 20 °C | 293.15 K |
| 37 °C | 310.15 K |
| 100 °C | 373.15 K |
Real-World Examples — °C to K
- 274.15 K — the equivalent of 1 °C (the smallest reference point)
- 283.15 K — a practical mid-range value (10 °C)
- 373.15 K — a common large-quantity reference (100 °C)
Applications of Celsius-to-Kelvin Conversion
The °C to K conversion is needed in meteorology, medicine, cooking, and material science. Here's where it specifically matters:
- International specifications: Products designed in one unit system must be documented for users who work in the other.
- Scientific and technical work: Research papers and engineering drawings specify temperature in a particular unit — accurate conversion prevents costly errors.
- Education: Physics, chemistry, and applied math curricula require fluency in temperature unit conversion.
- Everyday tasks: Cooking, construction, fitness, and travel all involve temperature conversions when switching between unit systems.
Common Mistakes When Converting Celsius to Kelvin
- Mistake: Forgetting to add 32 when converting C→F (a partial formula)
- Mistake: Using the wrong formula direction (multiplying instead of dividing)
- Mistake: Confusing Kelvin with Celsius in scientific calculations
Frequently Asked Questions — Celsius to Kelvin
How do you convert Celsius to Kelvin?
Add 273.15. K = °C + 273.15. No multiplication needed.
What is 0°C in Kelvin?
0°C = 273.15 K — the freezing point of water.
What is absolute zero in Celsius?
Absolute zero = 0 K = −273.15°C — the lowest possible temperature.
Why is Kelvin used in science?
Kelvin starts at absolute zero (no negative values), which is required for thermodynamic equations like the ideal gas law (PV = nRT) and the Stefan-Boltzmann radiation law.
What is body temperature in Kelvin?
37°C = 310.15 K.
Conclusion
Converting Celsius to Kelvin: use the formula K = °C + 273.15. The converter above handles any value instantly. Refer to the table above for quick reference values, and bookmark this page for fast °C to K access.