Historical Temperature ScalesReaumur to Celsius

Réaumur to Celsius

Snapshot

1 Réaumur equals 1.25 Celsius. Conversion Encyclopedia uses the same fixed conversion basis across the calculator, common values, and reverse page for this page.

Reference basis: This conversion uses a scale-and-offset equation (°C = °Ré * 1.25).
Example: For 20 Réaumur, the converted value equals 25 Celsius.
Use the reverse page if you need the opposite direction with the same basis.

Use the interactive calculator below for custom values and the common-value table for quick checks.

Interactive conversion

Converter Calculator

1.25 Celsius (°C)

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Machine access

Available to apps and AI agents

Réaumur to Celsius can be requested through Conversion Encyclopedia's structured interfaces by software and compatible AI agents. The identifiers below select the same calculation as the calculator.

Machine-readable identifiers

Conversion family: historical-temperature-scales
Source unit: reaumur
Target unit: celsius

The JSON API and OpenAPI specification use the identifiers to reach the conversion engine. WebMCP lets compatible AI agents request the same calculation.

Example API request and response

POST /api/v1/convert

Request

{
  "family": "historical-temperature-scales",
  "value": 1,
  "from": "reaumur",
  "to": "celsius"
}

Essential response

{
  "ok": true,
  "conversion": {
    "family": "historical-temperature-scales",
    "value": 1,
    "from": "reaumur",
    "to": "celsius",
    "result": {
      "raw": 1.25,
      "display": "1.25"
    },
    "canonicalPath": "/historical-temperature-scales/reaumur-to-celsius/"
  }
}

Full API documentation

Explanation

Use this page when you want a direct Réaumur to Celsius conversion. On this page, 1 Réaumur equals 1.25 Celsius.

Historical temperature scales can differ by degree size, zero reference, or both, so this route uses the exact direction-specific equation °C = °Ré x 1.25 instead of one shared factor.

Réaumur (deg Re): a historical temperature scale where water freezes at 0 deg Re and boils at 80 deg Re.

Celsius (deg C): a modern relative temperature scale widely used in science, weather, and everyday measurement.

This route is useful when translating legacy Réaumur references into celsius values, or when comparing older scientific and industrial records with modern scales.

This conversion uses an affine or exact linear historical-scale equation, so forward and reverse pages must keep their own dedicated formulas to stay numerically aligned.

Method & Reference

Method basis: exact affine formula (scale + offset) shown in Snapshot.
Equation reference: °C = °Ré * 1.25
Consistency rule: forward and reverse pages use inverse equations to preserve scale reference points.

Reference note

This Réaumur to Celsius page uses explicit historical scale equations (scale + offset), not a simple multiplier.

Historical temperature scales are reconstructed from standard reference definitions.
Forward and reverse directions use inverse formulas, so each direction has its own dedicated page.

Common Conversion Values

Réaumur (°Ré)	Celsius (°C)
-40	-50
0	0
20	25
32	40
80	100
100	125

Questions & answers

Frequently Asked Questions

What is 1 Réaumur in Celsius?

1 Réaumur equals 1.25 Celsius on this page.

What equation does this Réaumur to Celsius page use?

This page uses °C = °Ré x 1.25, and the same equation drives the direct answer, calculator, table, and FAQ.

Is there a reverse page for Celsius to Réaumur?

Yes. The reverse direction has its own page at °C to °Ré, where the inverse equation is used so the mirror route stays numerically aligned.