K to °C Converter
Convert Kelvin temperatures into Celsius values
Kelvin to Celsius FAQ
How do you convert Kelvin to Celsius exactly?
The conversion is straightforward: °C = K − 273.15. Kelvin and Celsius use the same degree size, so you only shift the zero point. For example, 293.15 K − 273.15 = 20 °C. This calculator applies the K to °C formula directly so you can focus on your science or engineering work instead of doing the subtraction every time.
Why do we subtract 273.15 from Kelvin?
The Kelvin scale starts at absolute zero (0 K), while the Celsius scale is anchored at the freezing point of water, 0 °C. The difference between these reference points is defined as exactly 273.15 degrees. That means °C = K − 273.15 and K = °C + 273.15. Subtracting 273.15 simply slides the temperature from an absolute scale into the everyday Celsius scale without changing the step size.
What is absolute zero in K and °C?
Absolute zero is the theoretical lowest possible temperature, where thermal motion in matter is at its minimum. It corresponds to:
- 0 K by definition
- −273.15 °C
The Kelvin scale is built so that absolute zero is 0 K, which is why it is the natural choice for thermodynamics and many physics and chemistry calculations.
When should I convert Kelvin to Celsius?
Kelvin is common in physics, chemistry, climate science and engineering, especially in formulas that depend on absolute temperature. Celsius is more intuitive for everyday thinking about weather, comfort and cooking. You will often convert Kelvin to Celsius when turning lab results, climate data or simulation outputs into numbers that a wider audience can picture: for example, explaining that 293.15 K is the same as 20 °C.
Is this converter accurate enough for lab work and homework?
Yes. The converter uses exactly the same relationship °C = K − 273.15 that appears in textbooks and standards. As long as your Kelvin measurement reflects the precision of your instrument, the Celsius result will be accurate enough for most coursework, lab reports and engineering calculations. You can then round the output to match the number of significant figures required by your class, journal or organisation.
How many decimal places of °C should I keep?
In many lab and engineering settings, one or two decimal places in °C is enough. For example, 298.15 K becomes 25.00 °C, which you might report as 25.0 °C. If your sensors only read to whole Kelvin values, there is no benefit in reporting more digits than that. This converter keeps full precision internally and then prints a clean Celsius value that you can round appropriately.
What if my starting temperature is in °C or °F instead?
If you already have Celsius, you do not need this converter: you can use °C directly for everyday purposes, or add 273.15 to get Kelvin when formulas demand it. If you start from Fahrenheit, you can use the dedicated °F to °C or °F to K tools first, or the full temperature conversion calculator when you need to move between several scales at once.
From absolute Kelvin readings to familiar Celsius values
This K to °C converter is designed for moments when your data, simulation outputs or reference tables are in Kelvin but you need to think or communicate in Celsius. That happens a lot in thermodynamics, reaction kinetics, material science, climate modelling and engineering specifications. Instead of repeatedly doing “K minus 273.15” on a calculator, you enter the Kelvin value once and get a line such as “293.15 K = 20 °C”.
1. One Kelvin input, one Celsius result
The interface stays deliberately minimal: a single input box for Kelvin and a result card underneath. You can type lab-like values around 250–350 K for everyday conditions, or much more extreme values for cryogenic or high-temperature work. The converter subtracts 273.15 exactly and formats the Celsius result in a way that is easy to read on phones, tablets and desktop screens.
If you later need to go the other way, from Celsius back to Kelvin, the “Swap Units” button takes you straight to the °C to K page. The two tools are built as a pair so you can move between everyday °C descriptions and absolute K values without changing your workflow.
2. Simple linear relationship between Kelvin and Celsius
Kelvin and Celsius are tightly linked: they share the same step size, so a 1 K temperature change is the same as a 1 °C change. The only difference is where the zero point sits. Celsius chooses the freezing point of water as 0 °C, while Kelvin sets 0 K at absolute zero. This leads directly to the compact conversion pair °C = K − 273.15 and K = °C + 273.15. The converter uses this relationship exactly, so your results line up with scientific calculators, textbooks and standards documents.
When you need to connect Kelvin and Celsius with other temperature scales such as Fahrenheit, the temperature conversion calculator provides a broader hub that keeps multiple units in sync on one page.
3. Common K to °C values at a glance
These example conversions match what the calculator outputs and help you build a feel for how Kelvin values map onto Celsius temperatures:
| Kelvin (K) | Celsius (°C) |
|---|---|
| 0 K | −273.15 °C (absolute zero) |
| 233.15 K | −40 °C |
| 273.15 K | 0 °C (water freezes) |
| 293.15 K | 20 °C (room temperature) |
| 298.15 K | 25 °C |
| 310.15 K | 37 °C (body temperature) |
| 323.15 K | 50 °C |
| 373.15 K | 100 °C (water boils) |
A quick mental rule is to subtract 273 instead of 273.15. For example, 300 K → roughly 27 °C. That is often close enough for rough reasoning. When you need the exact value for equations, documentation or assessment, this converter uses the full 273.15 offset so your numbers stay consistent and reproducible.
4. Where the K to °C converter shines
You will most often reach for this tool in situations like:
- Physics and thermodynamics — converting Kelvin values from equations and simulations into Celsius for interpretation and communication.
- Chemistry and reaction kinetics — turning Kelvin-based temperatures in rate laws into °C values that match lab conditions.
- Climate and atmospheric science — expressing model outputs, profiles and anomalies in Celsius for reports and visualisations.
- Engineering and process control — relating internal Kelvin-based calculations to Celsius values used in specs and control charts.
- Education and homework — double-checking manual K to °C conversions in problem sets and worked examples.
Because it follows the official linear relationship between Kelvin and Celsius, you can come back to this Kelvin to Celsius converter any time and get consistent, predictable results that fit both classroom work and real-world lab and engineering tasks.
References and further reading on Kelvin and Celsius
These references explain how the Kelvin and Celsius temperature scales are defined and used:
- Kelvin — covers the Kelvin scale as the SI base unit of thermodynamic temperature.
- Celsius — describes the Celsius scale, its history and connection to Kelvin.
- SI Units — Temperature (NIST) — provides official background on temperature units and the Kelvin/Celsius relationship.
For critical scientific, industrial or regulatory work, always follow your organisation’s official conversion and rounding procedures when moving between Kelvin, Celsius and other temperature units.