Delisle to Kelvin (°De to K)
1 degree Delisle equals 372.4833333 kelvins.
How to convert degrees Delisle to kelvins
Converting degrees Delisle to kelvins is not a simple multiplication, so use the formula below.
K = °De × -0.6666666667 + 373.15
Example: 10 degrees Delisle = 366.4833333 kelvins.
Temperature scales have different zero points, so converting is not just multiplication. Differences in degrees convert differently from absolute readings.
About these units
Degree Delisle (°De)
An inverted scale devised by Joseph-Nicolas Delisle in 1732 and later fixed with water boiling at 0° and freezing at 150°, so temperatures rise as it gets colder. Used in Russia for roughly a century.
Temperatures on the Delisle scale rise as things get colder, a reversal found in very few thermometer systems. Joseph-Nicolas Delisle, a French astronomer, built a mercury thermometer in 1732 with zero at the boiling point of water and measured the contraction of the mercury in hundred-thousandths. Peter the Great had invited him to Russia in 1725 to found an observatory in St. Petersburg, and his instruments were usually graduated to 2,400 or 2,700 divisions, a range suited to the severe local winters.
In 1738 Josias Weitbrecht, a colleague in St. Petersburg, recalibrated the instrument between two fixed points, 0 for boiling water and 150 for freezing. He sent such thermometers to scholars, among them Anders Celsius, whose own first scale was also inverted, running from 0 at boiling to 100 at freezing, before it was flipped after his death. Wikipedia says the Delisle thermometer stayed in use in Russia for almost a century, though that claim lacks a citation.
One degree Delisle is two thirds of a kelvin or Celsius degree. To convert, subtract two thirds of the Delisle reading from 100 to get Celsius, or from 373.15 to get kelvin. Boiling water is therefore 0 and freezing water is 150, so an ordinary winter day reads well above 100.
0 degrees Delisle = 373.15 kelvins (exactly).
Sources: Wikipedia: Delisle scale
Kelvin (K)
The SI base unit of temperature. Zero kelvin is absolute zero, where particles have minimal thermal motion. A kelvin step is the same size as a Celsius degree.
Lord Kelvin, born William Thomson, published an absolute temperature scale in 1848 and refined it with James Joule in 1854. Its zero sits at absolute zero, and its degree is the same size as a Celsius degree. The kelvin entered the SI in 1954, defined as 1/273.16 of the thermodynamic temperature of the triple point of water, where ice, liquid and vapor coexist. In 1967 the 13th CGPM renamed the unit from the degree Kelvin to simply the kelvin, with symbol K, and no word degree.
Since 20 May 2019 the kelvin has been defined by fixing the Boltzmann constant at exactly 1.380649 times 10 to the minus 23 joule per kelvin, which frees it from the properties of any one substance. Scientists use it for stars and cryogenics, and lighting designers use it for color temperature. NIST notes that incandescent bulbs run near 3,000 K, daylight lamps at 5,000 to 5,600 K, and the Sun's surface at about 5,800 K. Room temperature, about 21 degrees Celsius, is roughly 294 K.
The kelvin is the reference unit for temperature on this site.
Sources: NIST: the kelvin and the SI redefinition; BIPM: 13th CGPM (1967), Resolution 3; Wikipedia: Kelvin
Related conversions
- Kelvin to Delisle (reverse)
- Delisle to Celsius
- Delisle to Fahrenheit
- Celsius to kelvin
- Fahrenheit to kelvin
- Rankine to kelvin
- Réaumur to kelvin
- Newton to kelvin
- Rømer to kelvin
See all temperature units.