What is the formula to convert Kelvin to Reaumur?

°Ré = (K − 273.15) × 4/5. Subtract 273.15 to get Celsius first, then multiply by 0.8.

What is the formula to convert Reaumur to Kelvin?

K = (°Ré × 5/4) + 273.15. Multiply the Reaumur value by 1.25 to get Celsius, then add 273.15.

What is absolute zero in Reaumur?

Absolute zero (0 K / −273.15°C) equals −218.52 °Ré on the Reaumur scale.

What are the freezing and boiling points of water in Reaumur?

Water freezes at 0 °Ré (273.15 K) and boils at 80 °Ré (373.15 K) at standard atmospheric pressure.

Why does the Reaumur scale go from 0 to 80?

René Antoine Ferchault de Réaumur defined his scale in 1730 with water freezing at 0 and boiling at 80, because the alcohol thermometer fluid he used expanded by 80 parts out of 1000 between those points.

Is the Reaumur scale still used today?

Rarely. It was once common in parts of Europe and Russia for food and brewing (cheese aging in France, for instance), but has been almost entirely replaced by Celsius.

Kelvin to Reaumur Converter

Name: Kelvin to Reaumur Converter
Availability: InStock
Author: Nham Vu

Enter a Kelvin value and instantly see its Reaumur (°Ré) equivalent, with the formula and a reference temperature table.

Temperature Converter

Kelvin (K)

Reaumur (°Ré)

°Ré

Reference Temperatures

Click a row to load it

Description	K	°Ré

Summary

Enter a Kelvin value and instantly see its Reaumur (°Ré) equivalent, with the formula and a reference temperature table.

How it works

Enter a Kelvin value in the input field.
The tool subtracts 273.15 to convert Kelvin to Celsius.
It then multiplies the Celsius value by 4/5 (0.8) to get degrees Reaumur.
Reverse conversion works by multiplying °Ré by 5/4 and adding 273.15.
The reference table lists common temperatures in both K and °Ré for quick lookup.

Use cases

Understand historical thermometer readings recorded in the Reaumur scale.
Cross-check Kelvin values from scientific literature against the Reaumur scale.
Study the history of temperature measurement and the Reaumur scale's origin.
Convert cryogenic temperatures from Kelvin to Reaumur for historical reference.
Teach thermodynamics by comparing multiple temperature scales side by side.

Frequently Asked Questions

Last updated: 2026-07-24 · Reviewed by Nham Vu