Delisle to Celsius, Fahrenheit, Kelvin & More Converter
Enter a temperature in degrees Delisle to convert it to Celsius, Fahrenheit, Kelvin, Rankine, Newton, Réaumur, and Rømer.
Delisle Temperature Conversion Tool
Delisle Temperature Conversion Formula
Where:
- \(D\) — temperature in degrees Delisle (°De)
- \(C\) — temperature in degrees Celsius (°C)
- \(F\) — temperature in degrees Fahrenheit (°F)
- \(K\) — temperature in kelvins (K)
- \(R\) — temperature in degrees Rankine (°R)
- \(N\) — temperature in degrees Newton (°N)
- \(Re\) — temperature in degrees Réaumur (°Re)
- \(Ro\) — temperature in degrees Rømer (°Rø)
First convert Delisle to Celsius, then use the Celsius value for each other scale. The Delisle scale runs in the opposite direction from Celsius: a larger Delisle reading represents a lower temperature.
Delisle Temperature Conversion – Calculation Example
Example: Convert the default input of 60 °De to all seven output units.
\[\begin{aligned}C&=100-\frac{2}{3}(60)=60\,^{\circ}\mathrm{C} \\ F&=\frac95(60)+32=140\,^{\circ}\mathrm{F} \\ K&=60+273.15=333.15\,\mathrm{K} \\ R&=\frac95(60)+491.67=599.67\,^{\circ}\mathrm{R} \\ N&=\frac{33}{100}(60)=19.8\,^{\circ}\mathrm{N} \\ Re&=\frac45(60)=48\,^{\circ}\mathrm{Re} \\ Ro&=\frac{21}{40}(60)+7.5=39\,^{\circ}\mathrm{R\o} \end{aligned}\]
Result: 60 °De equals 60 °C, 140 °F, 333.15 K, 599.67 °R, 19.8 °N, 48 °Re, and 39 °Rø.
How to use the calculator
- Find the field labeled Temperature in Delisle.
- Enter your reading in degrees Delisle (°De). The default value is 60, which you can leave in place to check the worked example.
- Read the results labeled Celsius, Fahrenheit, Kelvin, Rankine, Newton, Reaumur, and Rømer. Each result is the same temperature expressed on a different scale.
- Replace the input whenever you need to convert another reading. A decimal input can be useful when transcribing a measurement recorded to a fraction of a degree.
Understanding Delisle temperature
The Delisle scale is a historical temperature scale that you may encounter in older records. At standard atmospheric pressure, water boils at 0 °De and freezes at 150 °De. This ordering is easy to misread if you are accustomed to Celsius or Fahrenheit: on the Delisle scale, temperatures rise as the numbers fall. For example, 60 °De is warmer than 150 °De.
The conversion starts with Celsius because the other six results can all be calculated from it. A change of 1 °De corresponds to a change of two-thirds of a Celsius degree in the opposite direction. Thus, moving from 60 °De to 61 °De lowers the equivalent Celsius temperature from 60 °C to about 59.33 °C. If you are comparing readings from several sources, converting them to one common scale helps prevent a reversed Delisle reading from being mistaken for a warming trend.
Each output serves a different context. Celsius and Fahrenheit are common in everyday temperature reporting; kelvin is widely used in scientific calculations. Rankine is an absolute scale with Fahrenheit-sized increments, while Newton, Réaumur, and Rømer are historical scales. If your next value is already in another unit, use the Celsius converter, Fahrenheit converter, or Kelvin converter instead.
Reference points and practical limits
| Reference point | Delisle | Celsius |
|---|---|---|
| Water boiling at standard atmospheric pressure | 0 °De | 100 °C |
| Worked example | 60 °De | 60 °C |
| Water freezing at standard atmospheric pressure | 150 °De | 0 °C |
| Absolute zero | 559.725 °De | −273.15 °C |
These are conversions between temperature readings, not instructions for measuring them. The water freezing and boiling reference points assume standard atmospheric pressure; the boiling temperature changes with pressure. A Delisle value below zero is mathematically valid and represents a temperature above 100 °C. Likewise, a value above 150 °De represents a temperature below 0 °C.
For ordinary thermodynamic temperatures, 559.725 °De corresponds to absolute zero. A larger Delisle input produces a negative kelvin result, so check the source reading and its unit if that occurs. Also distinguish °R for Rankine from °Rø for Rømer: their names and symbols are similar, but their numerical results are not interchangeable.
The displayed results may be rounded. When checking a historical measurement, retain the precision justified by the original record rather than treating extra decimal places in a converted value as newly measured detail. If a source lists a different temperature unit, confirm the unit before entering its number as Delisle.
Frequently Asked Questions
How do I convert Celsius to Delisle?
Subtract the Celsius temperature from 100, then multiply by 1.5: \(D=\frac{3}{2}(100-C)\). For example, 20 °C is \(\frac{3}{2}(100-20)=120\) °De. This is the reverse of converting a Delisle reading to Celsius.
Can I convert Fahrenheit directly to Delisle?
Yes. First express Fahrenheit as Celsius within a single formula: \(D=\frac{3}{2}\left(100-\frac{5}{9}(F-32)\right)\). For example, 68 °F gives \(D=\frac{3}{2}(100-20)=120\) °De. Keep the full intermediate value if your Fahrenheit reading has decimals.
What is room temperature in degrees Delisle?
A typical indoor range of 20–22 °C is about 120–117 °De. The order is reversed because higher Celsius temperatures have lower Delisle readings. Room temperature is not a fixed reference point; the actual reading depends on the building, season, and intended use.
How do I convert a temperature change in Delisle degrees?
Multiply the change in Delisle readings by \(-\frac{2}{3}\) to get the change in Celsius degrees. A rise of 9 °De therefore means a drop of 6 °C, or 10.8 °F. For a temperature difference, do not add the offsets used when converting actual readings.
Is a degree Newton a unit of force?
No. The degree Newton (°N) is a unit on a historical temperature scale; the newton (N) is the SI unit of force. The degree symbol matters. If an old record lists “N” without context, check whether it describes temperature or force before interpreting or converting the number.
Why do I get a slightly different result when I convert the displayed Celsius value?
The displayed Celsius result may be rounded, while the other units are calculated from the unrounded value. Using rounded Celsius as an intermediate step can therefore produce a small difference. For a hand calculation, retain extra digits until the final result, then round to a precision appropriate for the original reading.