Convert Kelvin to Delisle
Convert kelvins to degrees delisle instantly. °De = 559.725 − (K × 3/2) — use the live calculator, the exact formula, a reference-temperature table and worked examples. Also check the Delisle to Kelvin converter for the reverse conversion.
Units explained
Kelvin
The kelvin (K) is the SI base unit of thermodynamic temperature, defined by fixing the Boltzmann constant k at exactly 1.380649×10⁻²³ J/K. Zero kelvin is absolute zero, the lowest temperature physically possible, and kelvin values are written without a degree sign.
Named for William Thomson, 1st Baron Kelvin, who in 1848 calculated the value of absolute zero (about −273 °C) and proposed an absolute thermodynamic scale. His title comes from the River Kelvin, which flows past the University of Glasgow in Scotland.
The universal temperature unit of science and engineering — physics, chemistry, astronomy, and materials science — and the standard for color temperature in photography, displays, and lighting (a 5600 K daylight bulb).
Proposed by William Thomson (Lord Kelvin) in 1848; adopted as an SI base unit by the 10th CGPM in 1954 and redefined through the fixed Boltzmann constant by the 26th CGPM, effective May 20, 2019.
Delisle
The degree Delisle (°De) is a famously reversed scale: water boils at 0 °De and freezes at 150 °De, so numbers increase as temperature falls. One degree Delisle corresponds to exactly −2/3 of a kelvin.
Invented by French astronomer Joseph-Nicolas Delisle while directing the observatory in St. Petersburg, Russia; his thermometers were originally graduated by the contraction of mercury cooling down from the boiling point of water.
Widely used in 18th-century Russia for about a century. Today it appears only in the history of thermometry, where it is the textbook example of an inverted temperature scale.
Created by Joseph-Nicolas Delisle in St. Petersburg in 1732; recalibrated to the familiar 150-division form by Josias Weitbrecht in 1738.
Kelvin to Delisle conversion formula
The exact relationship between kelvins and degrees delisle:
To convert kelvins to degrees delisle, multiply the value by 3/2 and subtract the result from 559.725. To reverse, multiply the value by 2/3 and subtract the result from 373.15.
Reference anchors: water freezes at 273.15 K = 150 °De and boils at 373.15 K = 0 °De (at standard atmospheric pressure).
How to use this converter
Type a value into the calculator. The result in degrees delisle updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Delisle to Kelvin converter for the reverse direction.
Step-by-step: convert kelvins to degrees delisle
- Write down the temperature in kelvins (K).
- Multiply the value by 3/2 and subtract the result from 559.725.
- The result is the same temperature expressed in degrees delisle (°De).
- To reverse, multiply the value by 2/3 and subtract the result from 373.15 — or open the Delisle to Kelvin converter.
Worked examples
Example 1 — Convert 310.15 K to °De (human body temperature):
559.725 − (310.15 × 3/2) = 94.5 °De
Example 2 — Convert 373.15 K to °De (the boiling point of water):
559.725 − (373.15 × 3/2) = 0 °De
Kelvin to Delisle conversion table
Physically meaningful reference temperatures, from absolute zero to the surface of the Sun, converted from kelvins to degrees delisle:
| Kelvin [K] | Delisle [°De] | Reference point |
|---|---|---|
| 0 | 559.725 | Absolute zero |
| 233.15 | 210 | Where Celsius and Fahrenheit coincide (−40°) |
| 255.3722222222 | 176.6666666667 | Zero Fahrenheit (0 °F) |
| 273.15 | 150 | Water freezes (0 °C / 32 °F) |
| 273.16 | 149.985 | Triple point of water |
| 283.15 | 135 | Cool day (10 °C / 50 °F) |
| 293.15 | 120 | Room temperature (20 °C / 68 °F) |
| 298.15 | 112.5 | Standard laboratory temperature (25 °C) |
| 303.15 | 105 | Hot day (30 °C / 86 °F) |
| 310.15 | 94.5 | Human body temperature (37 °C / 98.6 °F) |
| 313.15 | 90 | Heat-wave day (40 °C / 104 °F) |
| 323.15 | 75 | Hot tap water (50 °C / 122 °F) |
| 373.15 | 0 | Water boils (100 °C / 212 °F) |
| 453.15 | -120 | Moderate baking oven (180 °C / 356 °F) |
| 5778 | -8107.275 | Surface of the Sun (≈5,505 °C) |
Frequently asked questions
What is 310.15 K in °De?
How do I convert kelvins to degrees delisle?
How do I convert degrees delisle back to kelvins?
At what temperature do the Kelvin and Delisle scales read the same number?
Can a temperature be below absolute zero?
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Sources & references
Conversion relationship (°De = 559.725 − (K × 3/2)) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- BIPM — International Temperature Scale of 1990 (ITS-90)
The internationally agreed practical temperature scale, defining fixed points (including the triple point of water at 273.16 K) and interpolation instruments used by national metrology institutes for thermometer calibration worldwide.
- CODATA Internationally Recommended Values of the Fundamental Physical Constants
Committee on Data of the International Science Council; authoritative source for the masses of fundamental particles (electron, proton, neutron) and the atomic mass constant.