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Fahrenheit to Rankine Converter
↔ Convert °R to °F instead

Common Conversions

°F °R
-459.67 0
-100 359.67
-40 419.67
0 459.67
32 491.67
68 527.67
77 536.67
100 559.67
212 671.67
500 959.67
1000 1459.67

Why this conversion matters in chemistry

Fahrenheit and Rankine share the same degree size — they differ only in where they put zero. Fahrenheit sets zero at the freezing point of a brine mixture; Rankine sets it at absolute zero. The offset is 459.67, which works out cleanly because absolute zero is exactly that many Fahrenheit degrees below 0 °F. Adding 459.67 is the first step any US-engineering ideal-gas calculation needs when temperatures arrive in Fahrenheit and the gas constant is in BTU/(lb-mol·°R). A 3000 °F combustion chamber lands at 3460 °R, which is the value PV = nRT actually wants on the right-hand side.

Formula

°R = °F + 459.67

Worked Examples

77 °F = 536.67 °R

Room temperature — the same as 25 °C, the standard reference temperature for thermodynamic data on both sides of the unit divide.

-459.67 °F = 0 °R

Absolute zero, where the Rankine scale starts and the third law of thermodynamics says entropy approaches a finite minimum.

32 °F = 491.67 °R

The freezing point of water — the most familiar Fahrenheit calibration anchor, and the value that makes the offset feel real.

212 °F = 671.67 °R

The boiling point of water at 1 atm, the other classic calibration point of the Fahrenheit scale.

Frequently Asked Questions

How do I convert Fahrenheit to Rankine?
Add 459.67. So 77 °F becomes 536.67 °R — the standard reference temperature in absolute units. The conversion is exact, since the offset matches the Fahrenheit value of absolute zero.
Why is the offset 459.67?
Absolute zero in Fahrenheit is exactly −459.67 °F. Rankine puts its zero at absolute zero while keeping Fahrenheit-sized degrees, so the conversion just slides the scale up by that fixed amount.
Does a chemist actually need Rankine?
Modern chemistry research stays in Kelvin. Rankine shows up in US engineering thermodynamics — natural-gas calculations, refrigeration cycles, gas-law problems where R is in BTU/(lb-mol·°R) — and any time a Fahrenheit temperature has to land in an absolute-scale equation in English units.
What is −40 °F in Rankine?
−40 °F is 419.67 °R. The −40 value is the famous crossover where Fahrenheit and Celsius scales agree (−40 °F = −40 °C), which works out to 233.15 K and 419.67 °R in absolute units.