# Fahrenheit to Réaumur (°F to °Ré)

Source: https://www.unitconvertercalculator.com/temperature/fahrenheit-to-reaumur/

To convert Fahrenheit to Reaumur, use the formula: Re = (F - 32) x 4/9. The Fahrenheit scale is the American everyday temperature standard, while the Reaumur scale is the historical European scale once standard in France and Germany. Water freezes at 32 degrees F (0 Re) and boils at 212 degrees F (80 Re).

## Formula

°F via Kelvin to °Ré

## Conversion Table

| Fahrenheit (°F) | Réaumur (°Ré) |
|---|---|
| -40 °F | -32 °Ré |
| 0 °F | -14.222222222224 °Ré |
| 10 °F | -9.777777777776 °Ré |
| 20 °F | -5.333333333336 °Ré |
| 32 °F | 0 °Ré |
| 40 °F | 3.555555555552 °Ré |
| 50 °F | 8 °Ré |
| 60 °F | 12.444444444448 °Ré |
| 68 °F | 16 °Ré |
| 72 °F | 17.777777777776 °Ré |
| 75 °F | 19.111111111112 °Ré |
| 80 °F | 21.333333333336 °Ré |
| 90 °F | 25.777777777776 °Ré |
| 98.6 °F | 29.6 °Ré |
| 100 °F | 30.222222222224 °Ré |
| 120 °F | 39.111111111112 °Ré |
| 150 °F | 52.444444444448 °Ré |
| 200 °F | 74.666666666664 °Ré |
| 212 °F | 80 °Ré |
| 250 °F | 96.888888888888 °Ré |
| 300 °F | 119.11111111111 °Ré |
| 350 °F | 141.33333333334 °Ré |
| 400 °F | 163.55555555555 °Ré |
| 450 °F | 185.77777777778 °Ré |
| 500 °F | 208 °Ré |

## Units

### Fahrenheit (°F)

A temperature scale where 32°F is the freezing point and 212°F is the boiling point of water. Primarily used in the United States.

### Réaumur (°Ré)

A historical temperature scale where water freezes at 0 °Ré and boils at 80 °Ré. Named after René Antoine Ferchault de Réaumur. Once widely used in Europe.

## Background

The Fahrenheit scale was created by Daniel Gabriel Fahrenheit, 1724, dominant in the US. The Reaumur scale was created by Rene Antoine Ferchault de Reaumur, 1730, once widespread in continental Europe. Converting between them bridges different eras and different measurement philosophies in the history of thermometry.

## Good to Know

The history of temperature measurement is the history of scientific collaboration and competition across borders. The Fahrenheit scale (dominant in the US) and the Reaumur scale (once widespread in continental Europe) represent different national contributions to solving the same fundamental problem: how to assign numbers to the sensation of hot and cold.

## FAQ

### How do you convert Fahrenheit to Reaumur?

Use the formula Re = (F - 32) x 4/9. At the freezing point of water: 32 F = 0 Re. At the boiling point: 212 F = 80 Re.

### When would you need to convert Fahrenheit to Reaumur?

This conversion is needed when interpreting historical scientific records, comparing temperature data across different measurement traditions, or completing engineering calculations that mix temperature scales from different national standards.

### What are the key reference points for both scales?

Water freezes at 32 F = 0 Re. Water boils at 212 F = 80 Re. These two fixed points anchor both scales and provide easy verification of any conversion calculation.

## Non-Frequently Asked Questions

### Would German bakers from 1850 recognize a Fahrenheit oven setting?

A German baker in 1850 used Reaumur degrees. An oven set to 180 Reaumur (225 C, 437 F) would be a mystery at 437 F. The baker would need to divide by roughly 2.25, then multiply by something they never learned. Baking across measurement systems is a recipe for confusion, if not burnt bread.

### Is converting Fahrenheit to Reaumur ever practically useful today?

Almost never. Reaumur is defunct in all modern applications. The only practical scenario is a food historian interpreting a 19th-century German or French recipe that specifies oven temperatures in Reaumur, using an American oven calibrated in Fahrenheit. This is an extraordinarily niche situation.

### If Fahrenheit met Reaumur at a dinner party, what would they discuss?

They would argue about the boiling point of water. Fahrenheit set it at 212 degrees; Reaumur at 80. Both would agree that water boils at the same physical temperature but disagree about what number to assign it. They would probably bond over being eventually replaced by Celsius, a Swede who was not even invited to the party.

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## See Also

- [Réaumur to Fahrenheit](https://www.unitconvertercalculator.com/temperature/reaumur-to-fahrenheit/)