What is 1 °R in Celsius?

1 °R = -272.59 °C. In the other direction, 1 °C = 493.47 °R.

What is the Rankine scale?

The Rankine scale is absolute like kelvin but uses the Fahrenheit degree. It appears in US thermodynamics and aerospace engineering.

What is the Celsius scale?

The Celsius scale places 0 at the freezing point of water and 100 at its boiling point at standard pressure. It is the civil temperature scale almost everywhere outside the United States.

What is 0 °R in Celsius?

0 °R is absolute zero, -273.15°C.

Unit-To-Unit Temperature conversion

Rankine to Celsius

1 °R = -272.59 °C

Rankine is Fahrenheit measured from absolute zero, so its degree matches Fahrenheit’s while its zero matches kelvin’s. It appears mainly in US thermodynamic tables.

Formula °C = (°R − 491.67) × 5/9

Rankine (°R) max 24 digits

Celsius (°C) max 24 digits

Type in either field — the other updates on every keystroke. Need other units? Open the full temperature converter.

Rankine to Celsius — quick reference
Rankine	Celsius
-40 °R	-295.37 °C
-20 °R	-284.26 °C
-10 °R	-278.71 °C
0 °R	-273.15 °C
10 °R	-267.59 °C
20 °R	-262.04 °C
25 °R	-259.26 °C
30 °R	-256.48 °C
37 °R	-252.59 °C
50 °R	-245.37 °C
75 °R	-231.48 °C
100 °R	-217.59 °C
200 °R	-162.04 °C

Celsius to Rankine — reverse
Celsius	Rankine
-40 °C	419.67 °R
-20 °C	455.67 °R
-10 °C	473.67 °R
0 °C	491.67 °R
10 °C	509.67 °R
20 °C	527.67 °R
25 °C	536.67 °R
30 °C	545.67 °R
37 °C	558.27 °R
50 °C	581.67 °R
75 °C	626.67 °R
100 °C	671.67 °R
200 °C	851.67 °R

Worked examples

Common values
Situation	From	To
Absolute zero	0 °R	-273.15 °C
Liquid nitrogen boils	139.25 °R	-195.79 °C
Water freezes	491.67 °R	0 °C
Room temperature	527.67 °R	20 °C
Body temperature	558.27 °R	37 °C
Water boils	671.67 °R	100 °C

Mental-math shortcut

Divide by 1.8 to get kelvin, then subtract 273.15.

Where this conversion comes up

The Rankine scale appears in some US engineering thermodynamics, such as engine and refrigeration calculations, because it keeps Fahrenheit-sized degrees.

Common mistakes

Rankine, written °R, is not the Réaumur scale. A reading of 0 °R is absolute zero, which is -273.15°C.

Background

The Scottish engineer William Rankine proposed the scale in 1859 as the Fahrenheit counterpart of kelvin.

Frequently asked

What is 1 °R in Celsius?: 1 °R = -272.59 °C. In the other direction, 1 °C = 493.47 °R.
What is the Rankine scale?: The Rankine scale is absolute like kelvin but uses the Fahrenheit degree. It appears in US thermodynamics and aerospace engineering.
What is the Celsius scale?: The Celsius scale places 0 at the freezing point of water and 100 at its boiling point at standard pressure. It is the civil temperature scale almost everywhere outside the United States.
What is 0 °R in Celsius?: 0 °R is absolute zero, -273.15°C.

Related temperature conversions

Celsius to Fahrenheit Fahrenheit to Celsius Celsius to Kelvin Kelvin to Celsius Fahrenheit to Kelvin