Celsius to Kelvin Conversion Formula — How to Convert °C to K
K = °C + 273.15
Quick mental estimate: K ≈ °C + 273
Step-by-Step °C to K Conversion Examples:
- •Room temperature:20 + 273.15 =293.15 K
- •Dry ice temperature:-78.5 + 273.15 =194.65 K
- •Gold melting point:1064 + 273.15 =1337.15 K
Why the Celsius to Kelvin Conversion Works & Common °C to K Converter Mistakes to Avoid
Kelvin is the SI base unit of temperature and starts at absolute zero. Celsius and Kelvin use the same degree size, so converting between them is just a matter of shifting the zero point.
The Common °C to K Converter Mistake: Using Celsius in the ideal gas law (PV = nRT). The gas constant R is defined with Kelvin.
Celsius to Kelvin Real-World Size Comparison Table
If you're working in a lab or studying thermodynamics, these are the reference points you'll see most often in textbooks and problem sets.
| Celsius (°C) | Kelvin (K) | Real-World Size Benchmark |
|---|---|---|
| -273.15 °C | 0 K | Absolute zero |
| -196 °C | 77.15 K | Liquid nitrogen |
| -78.5 °C | 194.65 K | Dry ice (solid CO₂) |
| 0 °C | 273.15 K | Ice point |
| 20 °C | 293.15 K | Standard room temperature |
| 37 °C | 310.15 K | Human body temperature |
| 100 °C | 373.15 K | Steam point |
| 5505 °C | 5778.15 K | Sun's surface |
When you need Kelvin instead of Celsius
Kelvin is the standard in three areas: gas-law equations, thermodynamics, and any physics calculation involving absolute temperature.
- • Use °C For: Weather forecasts, Everyday cooking, Clinical thermometers, Any consumer-facing temperature
- • Use K For: Ideal gas law (PV = nRT), Arrhenius equation, Blackbody radiation (Planck's law), Astronomy and astrophysics
Rule of Thumb: If your equation contains R or involves absolute temperature, use Kelvin.
°C to K Converter in Spreadsheets — Spreadsheet Shortcut (Excel & Google Sheets)
=A1+273.15 for Celsius → Kelvin. =A1-273.15 for the reverse.
Celsius to Kelvin Conversion — Frequently Asked Questions
How do I convert Celsius to Kelvin?
Add 273.15. For example, 25°C + 273.15 = 298.15 K.
What is absolute zero in Celsius?
−273.15°C. That's exactly 0 K.
Why doesn't Kelvin use a degree symbol?
Kelvin is an absolute scale, so it's written as just 'K' — not '°K'.
Can anything be colder than 0 Kelvin?
No. Absolute zero is the theoretical lower limit.
°C to K Quick-Reference Conversion Table
The temperature conversions that come up most often in science and lab work.
| To convert | Operation | Example |
|---|---|---|
| °C → K | + 273.15 | 25°C → 298.15 K |
| K → °C | − 273.15 | 373.15 K → 100°C |
| °C → °F | (× 9/5) + 32 | 100°C → 212°F |
| °F → °C | (− 32) × 5/9 | 32°F → 0°C |