Delisle, Newton & Rømer Converter
Explore three historical temperature scales — Delisle, Newton and Rømer — and convert them to and from today’s Celsius, Fahrenheit and Kelvin.
How to use the Delisle, Newton & Rømer Converter
- Enter a temperature.
- Choose its scale.
- Read the value on all seven scales.
How it works
- Delisle (1732): °De = (100 − °C) × 3/2. Water boils at 0 °De and freezes at 150 °De — higher numbers are colder.
- Newton (c. 1700): °N = °C × 33/100. Isaac Newton set freezing water at 0 and body heat at 12; boiling water is 33 °N.
- Rømer (1701): °Rø = °C × 21/40 + 7.5. Ole Rømer put freezing brine at 0 and boiling water at 60; water freezes at 7.5 °Rø. Fahrenheit later based his scale on Rømer’s.
Historical scales compared
| °C | °De | °N | °Rø |
|---|---|---|---|
| -40 | 210 | -13.2 | -13.5 |
| -10 | 165 | -3.3 | 2.25 |
| 0 | 150 | 0 | 7.5 |
| 20 | 120 | 6.6 | 18 |
| 37 | 94.5 | 12.21 | 26.93 |
| 50 | 75 | 16.5 | 33.75 |
| 100 | 0 | 33 | 60 |
| 200 | -150 | 66 | 112.5 |
Frequently asked questions
What is 100 °C in Delisle?
0 °De — Delisle starts at the boiling point of water.
What is body temperature in Newton degrees?
About 12.2 °N (37 °C × 33/100).
How did Rømer influence Fahrenheit?
Fahrenheit visited Rømer in 1708 and adapted his scale, multiplying it to avoid fractions — which led to the 32 and 212 fixed points.
Are these scales used today?
No — they are of historical interest and appear in science history and puzzles.