# Celsius to Delisle (°C to °De)

Source: https://www.unitconvertercalculator.com/temperature/celsius-to-delisle/

To convert Celsius to Delisle, subtract the Celsius temperature from 100 and multiply by 3/2. The Delisle scale is a historical temperature scale that runs in reverse - higher numbers mean lower temperatures. It has no modern applications but appears in historical science and physics education.

## Formula

°De = (100 − °C) × 3/2

## Conversion Table

| Celsius (°C) | Delisle (°De) |
|---|---|
| -40 °C | 210 °De |
| -20 °C | 180 °De |
| -10 °C | 165 °De |
| 0 °C | 150 °De |
| 5 °C | 142.5 °De |
| 10 °C | 135 °De |
| 15 °C | 127.5 °De |
| 20 °C | 120 °De |
| 25 °C | 112.5 °De |
| 30 °C | 105 °De |
| 36 °C | 96 °De |
| 37 °C | 94.5 °De |
| 40 °C | 90 °De |
| 50 °C | 75 °De |
| 60 °C | 60 °De |
| 80 °C | 30 °De |
| 100 °C | 0 °De |
| 150 °C | -75 °De |
| 180 °C | -120 °De |
| 200 °C | -150 °De |
| 220 °C | -180 °De |
| 250 °C | -225 °De |
| 300 °C | -300 °De |
| 500 °C | -600 °De |
| 1000 °C | -1350 °De |

## Units

### Celsius (°C)

A metric temperature scale where 0°C is the freezing point and 100°C is the boiling point of water. Used worldwide except in the US.

### Delisle (°De)

A historical inverted temperature scale invented by Joseph-Nicolas Delisle in 1732. Water boils at 0 °De and freezes at 150 °De. Higher numbers mean colder temperatures.

## Background

Room temperature of 20°C equals 120°De. Boiling water (100°C) is 0°De, and freezing water (0°C) is 150°De. The inverted nature of the Delisle scale can be confusing, but the conversion formula is straightforward. This scale was used in Russia from 1732 until about 1790.

## Good to Know

The Delisle scale is purely of historical interest. It is sometimes included in physics education to illustrate that temperature scales are human constructs and can run in either direction.

## FAQ

### What is the formula for Celsius to Delisle?

The formula is: °De = (100 − °C) × 3/2. For example, 25°C: (100 − 25) × 3/2 = 112.5°De. Note that the scale runs backwards: higher Delisle values mean lower temperatures.

### What is 0°C in Delisle?

0°C equals 150°De. On the Delisle scale, the freezing point of water is at 150 degrees, while boiling is at 0 degrees.

### Why does the Delisle scale run backwards?

Joseph-Nicolas Delisle designed his thermometer to measure contraction of mercury from the boiling point downward. Each degree represented a unit of mercury contraction, so colder temperatures produced higher numbers.

## Non-Frequently Asked Questions

### Did Mr. Celsius like it hot or cold?

Anders Celsius was Swedish, so he was used to cold. Ironically, he originally designed his scale backwards: 100 for freezing, 0 for boiling. A colleague, Carl Linnaeus, flipped it after Celsius died. So the Celsius scale is actually the anti-Celsius scale.

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## See Also

- [Delisle to Celsius](https://www.unitconvertercalculator.com/temperature/delisle-to-celsius/)