Convert Delisle to Celsius

Convert Delisle (°De) to Celsius (°C) instantly and accurately.

Conversion Formula

°C = 100 − °De × 2/3

About Delisle

Delisle (°De) was created by French astronomer Joseph-Nicolas Delisle in 1732 and used in Russia for nearly a century before metrication. Uniquely, the scale is inverted: it increases as temperature decreases. Water boils at 0°De and freezes at 150°De - the opposite of Celsius. Delisle calibrated his mercury thermometer against the boiling point of water, assigning it zero. The scale was adopted by the Russian Academy of Sciences and used by astronomers and naturalists across the Russian Empire throughout the 18th century. It still appears in historical scientific records from that era.

About Celsius

Celsius (°C) is the most widely used temperature scale worldwide, named after Swedish astronomer Anders Celsius (1742). It's based on the freezing point of water at 0°C and boiling point at 100°C under standard atmospheric pressure (1 atmosphere). This makes it intuitive for daily use: room temperature is around 20-22°C, body temperature is 37°C, and a hot summer day might reach 35-40°C. It's the standard in science, medicine, and weather reporting in most countries.

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