How to convert degrees Celsius to kelvins
Temperature scales have different zero points, so the conversion multiplies and then adds an offset:
K = °C × 1 + 273.15
°C = (K − 273.15) ÷ 1
Example: -273.15 °C → -273.15 × 1 + 273.15 = 0 K.
To convert the other way, use the kelvins to degrees Celsius converter.
Everyday values
| Degrees Celsius | Kelvins | For example |
|---|---|---|
| -273.15 °C | 0 K | absolute zero |
| 0 °C | 273.15 K | water freezes |
| 20 °C | 293.15 K | room temperature |
| 100 °C | 373.15 K | water boils |
When you need this conversion
Kelvin is the scientific temperature scale. It starts at absolute zero, so there are no negative kelvins, and it is written without a degree sign (300 K, not 300 °K). One kelvin step is the same size as one degree Celsius, so you only add 273.15.
Degree Celsius to kelvin conversion table
| °C | K | °C | K |
|---|---|---|---|
| -40 °C | 233.15 K | 60 °C | 333.15 K |
| -30 °C | 243.15 K | 70 °C | 343.15 K |
| -20 °C | 253.15 K | 80 °C | 353.15 K |
| -10 °C | 263.15 K | 90 °C | 363.15 K |
| 0 °C | 273.15 K | 100 °C | 373.15 K |
| 10 °C | 283.15 K | 110 °C | 383.15 K |
| 20 °C | 293.15 K | 120 °C | 393.15 K |
| 30 °C | 303.15 K | 130 °C | 403.15 K |
| 40 °C | 313.15 K | 140 °C | 413.15 K |
| 50 °C | 323.15 K | 150 °C | 423.15 K |
About the units
- Degree Celsius (°C): the kelvin scale shifted by 273.15.
- Kelvin (K): the SI base unit of temperature, starting at absolute zero.
Both are units of temperature. The conversion factor comes from the exact definitions above.
Frequently asked questions
What is the formula for degrees Celsius to kelvins?
K = °C × 1 + 273.15. For example, -273.15 °C is 0 K.
How do I convert degrees Celsius to kelvins?
Use K = °C × 1 + 273.15.
What is -273.15 °C in kelvins?
-273.15 °C = 0 K.
What is 0 °C in kelvins?
0 °C = 273.15 K.
Sources
- NIST Special Publication 811 (2008), Guide for the Use of the International System of Units (SI), Appendix B: conversion factors.
- NIST Handbook 44 (2024), Appendix C: General tables of units of measurement.
Last reviewed 5 October 2026. Results are estimates; see our disclaimer.