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CalcChef

Temperature Unit Converter

Convert between °C, °F, K, °R and four old scales: Delisle, Newton, Réaumur and Rømer. 0 °C = 32 °F = 273.15 K, and 180 °C is 356 °F. How it works

Use the Temperature Unit Converter

Result
32 °F
From 0 °C

1 Celsius ≈ 33.8 Fahrenheit

Celsius — Common Use

Standard metric temperature scale. Used worldwide for weather reporting, scientific research, and everyday temperature measurement. 0°C = freezing point of water, 100°C = boiling point.

Reference

About the Temperature Unit Converter

0 °C is 32 °F, 273.15 K and 491.67 °R, and 100 °C is 212 °F. To change Celsius to Fahrenheit, multiply by 9/5 and add 32; to change Fahrenheit to Celsius, subtract 32 and multiply by 5/9. Kelvin and Rankine start at absolute zero, so K = °C + 273.15 and °R = °F + 459.67.

Oven temperatures in °C, °F and kelvin

°C°FK
150302423.15
160320433.15
175347448.15
180356453.15
190374463.15
200392473.15
220428493.15
230446503.15

Exact results of the conversion; ovens and recipes round these to the nearest 5 or 10 degrees.

Reference points on four scales

Point°C°FK°R
Absolute zero-273.15-459.6700
Same number on both scales-40-40233.15419.67
Water freezes032273.15491.67
Room temperature2169.8294.15529.47
Human body3798.6310.15558.27
Water boils100212373.15671.67

Room temperature and human body are the converter’s own reference rows (21 °C and 37 °C), not medical or comfort statements.

How to use this tool

  1. Type a value in the From box and pick its scale, or type in the To box to work backward.
  2. Pick the To scale. The two boxes stay in step, and the line under them shows what 1 of the From scale equals.
  3. Use a quick button (freezing point, room temperature, body temperature, boiling point, absolute zero) or a row of the reference table to load a value.

Frequently asked questions

How do I convert Celsius to Fahrenheit?
°F = °C × 9/5 + 32. 180 °C is 356 °F, 37 °C is 98.6 °F and 21 °C is 69.8 °F.
How do I convert Fahrenheit to Celsius?
°C = (°F − 32) × 5/9. 350 °F is 176.667 °C, 400 °F is 204.444 °C, 450 °F is 232.222 °C and 72 °F is 22.2222 °C.
At what temperature are Celsius and Fahrenheit the same?
At -40. -40 °C and -40 °F are the same temperature, which is 233.15 K.
What is absolute zero in Celsius, Fahrenheit and Kelvin?
Absolute zero is -273.15 °C, -459.67 °F, 0 K and 0 °R. The converter accepts it and gives a message with no result for anything colder.
What is the difference between Kelvin and Celsius?
The degree is the same size and the zero point differs: K = °C + 273.15. A Rankine degree is the size of a Fahrenheit degree, and °R = K × 9/5.
Where do water’s freezing and boiling points fall on the Réaumur, Rømer, Newton and Delisle scales?
Réaumur puts them at 0 and 80, Rømer at 7.5 and 60, Newton at 0 and 33. Delisle counts down from boiling: 0 °De is boiling water and 150 °De is freezing, so a higher Delisle number is colder.

Ovens, weather and old scales

A European recipe that bakes at 180 °C needs 356 °F on a US oven dial, and a US recipe's 350 °F is 176.667 °C, which most ovens round to 175 or 180. A weather app showing 72 °F means 22.2222 °C, and a 30 °C forecast is 86 °F. A thermometer reading of 38 °C is 100.4 °F. Kelvin is the scale of physics and chemistry homework, where gas-law formulas need absolute temperature, and Rankine is its Fahrenheit-sized partner in some US engineering tables. Delisle, Newton, Réaumur and Rømer turn up in old books and instrument scales; type the reading on the old scale and read it in °C beside it.

You can type in either box: the other one follows, so 100.4 in the °F box gives 38 in the °C box.

Every scale goes through Celsius

Formulas from °C (x):

  • Fahrenheit: x × 9/5 + 32

  • Kelvin: x + 273.15

  • Rankine: (x + 273.15) × 9/5

  • Delisle: (100 − x) × 3/2

  • Newton: x × 33/100

  • Réaumur: x × 4/5

  • Rømer: x × 21/40 + 7.5

To go the other way, the formula is turned around: °C = (°F − 32) × 5/9. Results show six significant digits, so 350 °F reads 176.667 °C.

Delisle runs backward: a higher Delisle number is a colder temperature, and 150 °De is the freezing point of water. A kelvin step and a Celsius step are the same size, and a Rankine step equals a Fahrenheit step.

Fun Fact: Daniel Fahrenheit proposed his scale in 1724 with 0 °F at the freezing point of a brine of ice, water and ammonium chloride, 32 °F at ice and water, and 96 °F at about human body temperature. The scale was later recalibrated so that water freezes at 32 °F and boils at 212 °F, 180 degrees apart.

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