Rankine to Celsius (°R to °C)
Result
-272.5944444 Celsius
Formula
°C = °R × 0.5555555556 − 273.15
The kelvin is the SI base unit, defined through the Boltzmann constant. A Celsius temperature is the kelvin temperature minus 273.15, and a Fahrenheit degree is 5/9 of a Celsius degree with water freezing at 32 °F. Rankine uses Fahrenheit-sized degrees from absolute zero.
Worked examples
- 1 °R × 0.5555555556 − 273.15 = -272.59444 °C
- 10 °R × 0.5555555556 − 273.15 = -267.59444 °C
- 100 °R × 0.5555555556 − 273.15 = -217.59444 °C
Common mistakes
- Temperature readings and temperature differences convert differently: a reading uses °F = °C × 9/5 + 32, but a change of 10 °C is a change of 18 °F (no +32).
- −40 is the same reading in °C and °F; the popular "double it and add 30" shortcut drifts several degrees away from about 10 °C.
- Kelvin is written without a degree sign (300 K) and cannot be negative.
Rankine to Celsius table
| Rankine (°R) | Celsius (°C) |
|---|---|
| 1 | -272.59444 |
| 2 | -272.03889 |
| 5 | -270.37222 |
| 10 | -267.59444 |
| 20 | -262.03889 |
| 50 | -245.37222 |
| 100 | -217.59444 |
| 1,000 | 282.40556 |
The units
- Rankine (°R)
- A unit of temperature.
- Celsius (°C)
- Celsius: the kelvin temperature minus 273.15. Water freezes at about 0 °C and boils at about 100 °C at sea level.
Sources for these factors
- The International System of Units (SI Brochure), 9th edition — BIPM
- Guide for the Use of the International System of Units (SP 811), Appendix B: conversion factors — NIST
- Handbook 44 (2024), Appendix C: General Tables of Units of Measurement — NIST
Last reviewed against these sources. An automated check recomputes every factor from its definition on each build. How we check accuracy