Celsius to Kelvin Converter
Temperature · unit-converter
Convert Celsius to Kelvin with offset-aware formulas (not simple ratio scaling), step-by-step lines, and reference tables. Uses 273.15 for Celsius–Kelvin offsets, R = (9/5) × K for kelvin–rankine, and °F–R offset 459.67.
About Celsius
Celsius is a metric scale where 0 °C is the freezing point of water and 100 °C is the boiling point at standard atmospheric pressure. It shares the same step size as kelvin (1 K = 1 °C interval).
About Kelvin
Kelvin is the SI base unit for thermodynamic temperature. 0 K is absolute zero. The triple point of water is 273.16 K by definition; this tool uses 273.15 for °C ↔ K in everyday conversions.
How to convert Celsius to Kelvin
From Celsius to Kelvin: K = °C + 273.15. Kelvin uses the same step as Celsius with a different zero at absolute zero.
0 °C = 273.15 K exactly with the usual ITS-90–aligned offset used in general science.
Unlike units with a single fixed ratio (meters to feet), absolute temperatures include an offset. Always use the full formula for this pair—do not “multiply only” by a scale factor unless you are computing a temperature difference (interval), where offsets cancel.
Examples
Example #1: Convert 273.15 c to Kelvin
273.150000°C + 273.15 = 546.300000K
→ 546.3 k
Example #2: Convert 300 c to Kelvin
300.000000°C + 273.15 = 573.150000K
→ 573.15 k
Summary
From Celsius to Kelvin: K = °C + 273.15. Kelvin uses the same step as Celsius with a different zero at absolute zero.
Relationship context
Converting Celsius to Kelvin uses different zeros and step sizes. You cannot multiply by a single ratio alone for every pair—you first express the same physical temperature in an intermediate form (Celsius is used inside this tool), then map to Kelvin. Unlike length or energy units, offsets matter for Celsius and Fahrenheit; kelvin and rankine are absolute scales linked by the exact factor 9/5.
Conversion tables
| Celsius (c) | Kelvin (k) |
|---|---|
| -40 | 233.15 |
| -20 | 253.15 |
| -10 | 263.15 |
| 0 | 273.15 |
| Celsius (c) | Kelvin (k) |
|---|---|
| 10 | 283.15 |
| 20 | 293.15 |
| 37 | 310.15 |
| 100 | 373.15 |