Temperature Conversion: All Four Scales
One place for Celsius, Fahrenheit, Kelvin and Rankine: conversion formulas, fixed points and a reference temperature chart.
From F C To
F
C
Four scales at a glance
| Scale | Water freezes | Water boils | Absolute zero |
|---|---|---|---|
| Celsius | 0 C | 100 C | -273.15 C |
| Fahrenheit | 32 F | 212 F | -459.67 F |
| Kelvin | 273.15 K | 373.15 K | 0 K |
| Rankine | 491.67 R | 671.67 R | 0 R |
Conversion matrix
| From | To | Formula |
|---|---|---|
| C | F | F = C x 9/5 + 32 |
| F | C | C = (F - 32) x 5/9 |
| C | K | K = C + 273.15 |
| K | C | C = K - 273.15 |
| F | R | R = F + 459.67 |
| R | F | F = R - 459.67 |
| F | K | K = (F + 459.67) x 5/9 |
| C | R | R = (C + 273.15) x 9/5 |
Reference temperature chart
| Fahrenheit | Celsius | Kelvin | Reference |
|---|---|---|---|
| -459.67 F | -273.15 C | 0 K | Absolute zero |
| -320.44 F | -195.8 C | 77.35 K | Liquid nitrogen |
| -40 F | -40 C | 233.15 K | Scales meet |
| 0 F | -17.78 C | 255.37 K | Freezing point (F) |
| 32 F | 0 C | 273.15 K | Water freezes |
| 68 F | 20 C | 293.15 K | Room temperature |
| 98.6 F | 37 C | 310.15 K | Body temperature |
| 212 F | 100 C | 373.15 K | Water boils |
| 350 F | 176.67 C | 449.82 K | Moderate oven |
| 450 F | 232.22 C | 505.37 K | Hot oven |
Which scale to use
- Everyday weather and cooking: Celsius almost everywhere, Fahrenheit in the US.
- Science and engineering: Kelvin, because it starts at absolute zero and needs no offset.
- US engineering thermodynamics: Rankine appears in some older references.
Related pages
Frequently Asked Questions
Which temperature scale do scientists use?
Kelvin, because it starts at absolute zero and needs no offset in formulas.
What is absolute zero in Fahrenheit?
-459.67 F, equal to -273.15 C, 0 K and 0 R.
Is Rankine still used?
Mainly in older US engineering thermodynamics references; it is Fahrenheit-sized degrees starting at absolute zero.