Réaumur (°Ré) to Celsius Converter

About this calculator

The Réaumur scale, devised by French scientist René Antoine Ferchault de Réaumur in 1730, sets water's freezing point at 0°Ré and boiling point at 80°Ré (rather than 100), so it converts to Celsius as °C = °Ré × 1.25 (and to Fahrenheit as °F = °Ré × 2.25 + 32).

Once the dominant temperature scale across much of continental Europe, Réaumur was largely displaced by Celsius in the 19th century, but it still turns up today in older Russian and French scientific literature, some traditional cheese-making and confectionery recipes, and historical texts, where this converter lets readers translate an antique reading into a familiar modern scale.