Celsius to Kelvin
Convert any value from c to k with full precision. Use the converter above for instant results, or read on for the exact formula, worked examples, common uses, and answers to frequently asked questions.
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About the C to K conversion
Temperature is one of the few common measurements where you cannot simply multiply by a conversion factor. Unlike length and weight, temperature scales have different zero points, so you need to apply an offset in addition to scaling. This converter handles the math for Celsius, Fahrenheit, Kelvin, Rankine, Réaumur, and the less common Delisle and Newton scales.
This page focuses specifically on converting c to k. Use the converter above for instant results, or read on for the exact formula, a worked example, and answers to common questions.
Where this conversion is used
Weather forecasts in the United States use Fahrenheit while most of the rest of the world uses Celsius. Scientists use Kelvin because it starts at absolute zero, the theoretical point where all thermal motion stops. Engineers working with thermodynamic calculations frequently convert between Rankine and Kelvin. Older European and Russian literature uses Réaumur.
If you frequently convert c to k, bookmark this page — the exact URL gives you instant access without searching, and the conversion widget is ready to use the moment the page loads.
Temperature formulas
Unlike most conversions, temperature scales have different zero points, so conversion uses both multiplication and an offset.
- Celsius → Fahrenheit: °F = (°C × 9/5) + 32
- Fahrenheit → Celsius: °C = (°F − 32) × 5/9
- Celsius → Kelvin: K = °C + 273.15
- Kelvin → Celsius: °C = K − 273.15
- Fahrenheit → Rankine: °R = °F + 459.67
- Celsius → Rankine: °R = (°C + 273.15) × 9/5
Sources and accuracy
The modern Celsius scale is defined using the triple point of water (0.01 °C) and absolute zero (−273.15 °C), as established by the BIPM and NIST. The Fahrenheit scale was originally defined using a brine solution and later standardized at 32 °F for the freezing point and 212 °F for the boiling point of water.
This page was reviewed against multiple authoritative references. Conversion factors are cross-checked with the NIST SP 811 guide, the BIPM SI brochure, ISO 80000, and where applicable, the historical references for older unit systems. If you spot an inconsistency or have a suggested improvement, please let us know via the contact page.
Important disclaimer: for mission-critical work — medical dosing, legal-for-trade measurements, aerospace, large-scale engineering, and financial calculations — always verify independently with the original source. This converter is intended for everyday conversions, education, and quick reference.
Practical tips
When converting temperature differences (not single temperatures), remember that 1 °C = 1.8 °F = 1 K = 1.8 °R. Many people forget the offset when converting weather or oven temperatures — enter the actual temperature (not a difference) above.
If you are converting large lists of values, use the swap button to instantly reverse direction without retyping. For decimal-heavy values you can paste them directly into the From field — the input accepts standard decimal notation, including negative values and scientific notation (for example, 1.23e-5).
Frequently asked questions
How accurate is this c to k converter?
It uses the official international conversion factors from NIST and BIPM with full double-precision floating-point accuracy. For everyday use the result is precise to many more decimal places than any practical measurement requires.
Can I convert in both directions?
Yes. Use the ⇄ button above to swap the From and To fields. You can also change either dropdown to any unit in the temperature category.
Do I need an internet connection?
Only for the first page load. Once the converter is loaded it runs entirely in your browser, so it works offline as well.
Is my data private?
Yes. The conversion calculation happens locally in your browser. The values you enter are never sent to any server.