# Degrees Celsius to kelvins converter

> Convert degrees Celsius to kelvins (Celsius to Kelvin) with the exact formula, a conversion chart and worked steps.

Interactive version: https://www.calcopenly.com/conversion/celsius-to-kelvin
Subject: Unit converters

A Celsius reading may describe weather, a room or an oven setting. Temperature scales use different zero points, so a ratio alone is insufficient. Converting a temperature reading is also different from converting a temperature difference, where the offset cancels.

Degrees Celsius and kelvins are not related by a single multiplier because the two scales start from different zero points, so the conversion uses a formula. 25 °C is 298.15 K.

The Celsius and kelvin scales have the same step size; a Fahrenheit degree is 5/9 of a Celsius degree. Absolute zero is 0 K, −273.15 °C or −459.67 °F, and inputs below it are rejected.

## Inputs

- **Degrees Celsius (°C)**

## Results

- Kelvins (K) — main result
- Conversion
- 1 K in degrees Celsius (°C)

## Formula

$$
K = {}^\circ C + 273.15
$$

## Worked examples

### 25 °C to K

- Degrees Celsius (°C): 25 °C
- **Kelvins: 298.15 K**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 0 °C to K

- Degrees Celsius (°C): 0 °C
- **Kelvins: 273.15 K**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 100 °C to K

- Degrees Celsius (°C): 100 °C
- **Kelvins: 373.15 K**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

## Questions

### When would I convert Celsius to Kelvin?

A Celsius reading may describe weather, a room or an oven setting. Temperature scales use different zero points, so a ratio alone is insufficient. Converting a temperature reading is also different from converting a temperature difference, where the offset cancels.

### What is the formula to convert Celsius to Kelvin?

Add 273.15: 25 °C is 298.15 K. Kelvin and Celsius degrees are the same size, so only the zero point differs.

### How accurate is the degrees Celsius to kelvins converter?

Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 3 worked examples whose answers come from independent sources; for example, “25 °C to K” is checked against Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions).

### Where does the method come from?

NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B; NIST Handbook 44, Appendix C: General tables of units of measurement; BIPM, The International System of Units (SI Brochure), 9th edition.

## Sources

- [NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B](https://www.nist.gov/pml/special-publication-811)
- [NIST Handbook 44, Appendix C: General tables of units of measurement](https://www.nist.gov/pml/weights-and-measures/publications/nist-handbooks/handbook-44)
- [BIPM, The International System of Units (SI Brochure), 9th edition](https://www.bipm.org/en/publications/si-brochure)