Conversions

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Conversions

Rankine to Réaumur Calculator.

Converts a temperature from Rankine to Réaumur and also shows the equivalent in Celsius and Fahrenheit.

Results update live as you type.
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Your inputs

How it works

  1. 1

    Enter the temperature in Rankine.

  2. 2

    Subtract 491.67 from the Rankine value to get Celsius.

  3. 3

    Multiply the Celsius value by 4/9 to get Réaumur.

  4. 4

    The result is displayed in Réaumur, with Celsius and Fahrenheit shown as extras.

(rankine - 491.67) * 4 / 9

Frequently asked questions

What is the freezing point of water in Réaumur?

0 °Ré, which corresponds to 491.67 °R.

What is the boiling point of water in Réaumur?

80 °Ré, which corresponds to 671.67 °R.

Can I enter negative Rankine values?

No, Rankine is an absolute temperature scale, so values below 0 °R are physically impossible.

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Results

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Réaumur

0°Ré

Celsius0°C
Fahrenheit0°F
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Estimate for general guidance only — verify important decisions with an appropriate professional.

How it works

Converts a temperature from Rankine to Réaumur and also shows the equivalent in Celsius and Fahrenheit.

  1. Enter the temperature in Rankine.
  2. Subtract 491.67 from the Rankine value to get Celsius.
  3. Multiply the Celsius value by 4/9 to get Réaumur.
  4. The result is displayed in Réaumur, with Celsius and Fahrenheit shown as extras.

Formulas

The math behind this calculator, written out so you can verify the result.

Rankine to Réaumur

°Ré = (°R - 491.67) × 4/9

First convert Rankine to Celsius by subtracting 491.67, then multiply by 4/9 to get Réaumur.

Example:

Input: °R = 500

Calculation: (500 - 491.67) × 4/9 = 8.33 × 4/9

Result: ≈ 3.70 °Ré

Real-world use cases

Where this calculation shows up in everyday life.

Scientific research

Convert historical temperature data recorded in Réaumur to modern Rankine for analysis.

Example: Old French lab notes use Réaumur; convert to Rankine for consistency.

Engineering applications

Some industrial processes still reference Réaumur; convert to Rankine for thermodynamic calculations.

Example: Checking a reactor temperature specified in Réaumur.

Education

Help students understand temperature scale conversions and absolute scales.

Example: Classroom exercise converting between Rankine and Réaumur.

Tips and common mistakes

Tips

  • Remember that Rankine is an absolute scale starting at absolute zero, so it never goes negative.
  • The Réaumur scale sets freezing at 0 and boiling at 80, so 1 °Ré = 1.25 °C.
  • Use the Celsius intermediate step to avoid mistakes: °Ré = (°C) × 4/5.
  • Double-check your arithmetic when converting between absolute and relative scales.

Common Mistakes to Avoid

  • Forgetting to subtract 491.67 before multiplying by 4/9.
  • Using 459.67 (the Fahrenheit offset) instead of 491.67.
  • Confusing Réaumur with Rankine or Rømer.

Assumptions and limitations

  • Use the stated inputs and units.
  • Results are estimates for planning and education.
  • Check measurements and source data before making an important decision.