Fahrenheit-sized degrees counted from absolute zero, so 0°R is −459.67°F. It appears in some US engineering work.

Converters Temperature

Temperature converter

From To 68

20 °C = 68 °F

Every unit at once

Local · offset as well as factor, unlike every other category

Celsius to Fahrenheit is × 9/5 then + 32; back the other way is − 32 then × 5/9. Kelvin is Celsius plus 273.15. Rankine is Fahrenheit measured from absolute zero.

How to convert temperature

1 Type the temperature.

2 Pick its scale.

3 Read all four at once.

Temperature is the odd one out among unit conversions, and the reason is that the scales do not share a zero. Every other conversion is a single multiplication, so ten of something is always ten times one of it; temperature needs an offset as well, which is why 20°C is 68°F but 40°C is not 136°F. It also means differences and absolute values convert differently: a rise of 10°C is a rise of 18°F, not 50°F. The single crossing point where the two scales agree is −40, which is genuinely −40 in both.

Questions

What is the formula for Celsius to Fahrenheit? −

Multiply by 9/5 and add 32. Reverse it by subtracting 32 first, then multiplying by 5/9.

At what temperature are C and F the same? +

Why does temperature need an offset? +

How do I convert a temperature difference? +

What is Rankine? +

Is it Kelvin or degrees Kelvin? +

Sources

BIPM — the International System of Units (SI)

Was this tool any good?

INTERNAL SIGNAL ONLY · WE USE IT TO FIND TOOLS WORTH REBUILDING