Rømer to Celsius (°Rø to °C)
1 degree Rømer equals -12.38095238 degrees Celsius.
How to convert degrees Rømer to degrees Celsius
Converting degrees Rømer to degrees Celsius is not a simple multiplication, so use the formula below.
°C = °Rø × 1.904761905 − 14.28571429
Example: 10 degrees Rømer = 4.761904762 degrees Celsius.
Temperature scales have different zero points, so converting is not just multiplication. Differences in degrees convert differently from absolute readings.
About these units
Degree Rømer (°Rø)
An early temperature scale devised by Ole Rømer around 1702: water freezes at 7.5° and boils at 60°. Fahrenheit based his scale on it.
Ole Rømer, the Danish astronomer better known for measuring the speed of light, devised this scale around 1702 for his own use. It is the second temperature scale on record, after Newton's from a year earlier. Water freezes at 7.5 degrees and boils at 60 degrees, so one degree equals 40/21 of a Celsius degree, about 1.905 degrees Celsius.
The odd 7.5 may come from his earlier choice of a lower fixed point, the cold of ammonium chloride brine. He apparently found that the freezing point of water lay about one eighth of the way up from that mark to boiling and moved the scale accordingly, though his exact reasoning is unknown.
Daniel Fahrenheit visited him in Copenhagen in 1708 and by 1713 was making thermometers on a scale largely borrowed from Rømer. He shifted freezing from 7.5 to 8 and quartered each degree, which gave 32 degrees. Rømer's notebook was only published in 1910.
0 degrees Rømer = 258.8642857 kelvins (approximately).
Sources: Wikipedia: Rømer scale; Wikipedia: Ole Rømer
Degree Celsius (°C)
The metric temperature scale used worldwide for weather and daily life: water freezes at 0 °C and boils at 100 °C at standard pressure. Named after Anders Celsius.
Anders Celsius, a Swedish astronomer, proposed a scale in 1742 that ran the opposite way from the one we use: 0 for the boiling point of water and 100 for its freezing point. Credit for flipping it is shared and partly disputed. French physicist Jean-Pierre Christin published a reversed mercury thermometer in 1743, Carl Linnaeus is usually credited with reversing it in 1744, the year Celsius died, and others in Sweden, including Pehr Elvius, Daniel Ekström and Mårten Strömer, are also named as independent developers.
For much of the nineteenth century the scale was called centigrade, until the CGPM and CIPM adopted the name degree Celsius in 1948, partly to honor Celsius and to avoid confusion with a French term for a subdivision of the gradian. From 1954 to 2019 it was defined through absolute zero and the triple point of water; since 2019 it is tied to the Boltzmann constant. Strictly, water boils at about 99.974 degrees on the modern international temperature scale, not exactly 100. Australian weather reports switched exclusively to Celsius in 1972.
0 degrees Celsius = 273.15 kelvins (exactly).
Sources: Wikipedia: Celsius; BIPM: 9th CGPM (1948), Resolution 7; NIST: the kelvin and the SI redefinition
Related conversions
- Celsius to Rømer (reverse)
- Rømer to kelvin
- Rømer to Fahrenheit
- Kelvin to Celsius
- Fahrenheit to Celsius
- Rankine to Celsius
- Réaumur to Celsius
- Delisle to Celsius
- Newton to Celsius
See all temperature units.