This converter changes degrees Réaumur into degrees Rankine. Temperature is the one conversion people most often get wrong, because the two scales differ in both the size of a degree and where zero sits, so a single multiplication is not enough.
An 18th-century scale with water freezing at 0 °Ré and boiling at 80 °Ré; it survives in some cheese and syrup making. An absolute scale with Fahrenheit-sized degrees, used in some US thermodynamics and aerospace work.
The correct relationship is °R = °Ré × 2.25 + 491.67. Enter any value — including negative ones — and the result updates immediately, with the reverse conversion shown underneath as a check.
The formula
°Ré- Your temperature in degrees Réaumur
0- The zero-point offset of the degrees Réaumur scale
2.25- The ratio of degree sizes between the two scales
°R- The converted temperature in degrees Rankine
How it works, step by step
- Enter the temperature in degrees Réaumur.
- The scale offset of 0 is removed first.
- The result is scaled by 2.25 to match the size of a degree Rankine.
- The degrees Rankine offset of 491.67 is added to land on the final value.
Worked examples
Room temperature (20 °Ré)
Applying °R = °Ré × 2.25 + 491.67 to 20 °Ré gives 536.67 °R. This is the value most thermostats sit near.
Body temperature (37 °Ré)
37 °Ré converts to 574.92 °R. Normal human body temperature is often quoted as this figure.
How to read your score
Frequently asked questions
What is the formula to convert degrees Réaumur to degrees Rankine?
°R = °Ré × 2.25 + 491.67. Unlike most unit conversions this one is not a single multiplication, because the two scales have different zero points as well as different degree sizes.
What is 0 °Ré in degrees Rankine?
0 °Ré equals 491.67 °R.
What is 100 °Ré in degrees Rankine?
100 °Ré equals 716.67 °R.
Why can I not just multiply by a single factor?
Because both scales are offset from each other. A factor alone works only when both scales share a zero point, which is true for kelvin and Rankine but not for Celsius and Fahrenheit. Skipping the offset is the most common source of wrong answers.
Is there a temperature where degrees Réaumur and degrees Rankine read the same?
Yes — the two scales cross at 393.34 °Ré.
What is a degree Réaumur?
An 18th-century scale with water freezing at 0 °Ré and boiling at 80 °Ré; it survives in some cheese and syrup making.
What is a degree Rankine?
An absolute scale with Fahrenheit-sized degrees, used in some US thermodynamics and aerospace work.
Degrees Réaumur to degrees Rankine reference table
| Degrees Réaumur | Degrees Rankine |
|---|---|
| -40 °Ré | 401.67 °R |
| -20 °Ré | 446.67 °R |
| -10 °Ré | 469.17 °R |
| 0 °Ré | 491.67 °R |
| 10 °Ré | 514.17 °R |
| 20 °Ré | 536.67 °R |
| 25 °Ré | 547.92 °R |
| 30 °Ré | 559.17 °R |
| 37 °Ré | 574.92 °R |
| 50 °Ré | 604.17 °R |
| 75 °Ré | 660.42 °R |
| 100 °Ré | 716.67 °R |
| 200 °Ré | 941.67 °R |
Includes the reference points that matter: water freezing and boiling, body temperature, and room temperature.