Free Kelvin Converter

Value

Quick Reference

°C = K − 273.15
°F = (K − 273.15) × 9/5 + 32
°R = K × 9/5
°Ré = (K − 273.15) × 4/5

0 K = −273.15°C = −459.67°F

0 K = 0°R = −218.52°Ré

Enter a value for instant conversion

This free temperature conversion calculator, the Kelvin Converter, provides instant equivalences between Kelvin and seven other temperature scales. Whether you need to convert Kelvin to Celsius for a science class, Kelvin to Fahrenheit for weather data, or explore less common scales like Rankine or Delisle, this online tool delivers accurate results at the click of a button. Below we explain the principles of the Kelvin scale, the conversion formulas, and how to use the converter effectively.

The Kelvin Scale

The Kelvin scale is an absolute thermodynamic temperature scale, established by Lord Kelvin (William Thomson) in the 1800s. It starts from absolute zero (0 K), the point where particles have minimal thermal motion. Unlike degrees Celsius or Fahrenheit, Kelvin values are not accompanied by a degree symbol; they are simply denoted with the letter “K”. Another key attribute is compatibility with SI metric prefixes: for example, one kilokelvin (kK) equals 1000 K, and one millikelvin (mK) equals 0.001 K. This makes the Kelvin scale flexible for both micro‑ and macro‑scale measurements.

Conversion Formulas

To convert a temperature $T_{\text{K}}$ in Kelvin to another scale, apply the corresponding formula from the table below.

Target Scale	Formula
Celsius (°C)	$T_{\text{C}} = T_{\text{K}} - 273.15$
Fahrenheit (°F)	$T_{\text{F}} = 1.8 \times T_{\text{K}} - 459.67$
Rankine (°R)	$T_{\text{R}} = 1.8 \times T_{\text{K}}$
Delisle (°De)	$T_{\text{De}} = -1.5 \times T_{\text{K}} + 559.725$
Newton (°N)	$T_{\text{N}} = 0.33 \times T_{\text{K}} - 90.1395$
Réaumur (°Ré)	$T_{\text{Ré}} = 0.8 \times T_{\text{K}} - 218.52$
Rømer (°Rø)	$T_{\text{Rø}} = 0.525 \times T_{\text{K}} - 135.90375$

These formulas involve only basic arithmetic operations—addition, subtraction, and multiplication—so you can easily verify the calculator’s output or perform conversions manually.

How to Use the Temperature Converter

Operating this free temperature conversion calculator is straightforward. Type a numerical value into the Kelvin input field; the tool instantly updates all equivalent temperatures in the seven other scales. Conversely, you can enter a value in any of the other units (such as degrees Celsius or Fahrenheit) to obtain its Kelvin equivalent. The converter also includes a Kelvin‑field adjustment feature that lets you explore SI multiples: enter a gigakelvin or a microkelvin, for example, and see the corresponding values across all scales.

Example: Kelvin to Fahrenheit and Kelvin to Celsius

Consider converting 500 K to Fahrenheit. Using the formula: multiply 500 by 1.8 to get 900, then subtract 459.67, resulting in 440.33°F. For a Kelvin‑to‑Celsius conversion, take 300 K: subtract 273.15 to obtain 26.85°C. These examples demonstrate how the core formulas work and how the calculator can instantly show such results.

FAQ

1. How do I convert Kelvin to Celsius using this converter?

Simply type a Kelvin value into the Kelvin input field; the calculator will immediately show the Celsius equivalent. The underlying formula is T(°C) = T(K) - 273.15.

2. What is the conversion formula from Kelvin to Fahrenheit?

The formula is T(°F) = 1.8 × T(K) - 459.67. For instance, 500 K converts to 440.33°F.

3. Can I use the converter to go from Celsius to Kelvin?

Yes. The converter supports bidirectional conversion: type a value in the Celsius (or any other unit) field, and it will display the corresponding Kelvin temperature automatically.

4. Why doesn't Kelvin use the degree symbol?

Kelvin is an absolute thermodynamic scale and an SI base unit. By convention, temperatures are stated with the letter K (e.g., 300 K) without a degree sign, to distinguish it from relative scales like Celsius or Fahrenheit.

How to Use

Enter a numeric value in the input field and select the temperature unit you want to convert from.
All equivalent values in other temperature units will be displayed instantly.
Use the result for your scientific calculations, engineering projects, or academic needs.