Temperature Converter

Convert between Celsius, Fahrenheit, Kelvin, and Rankine temperature scales instantly and accurately.

Temperature Converter tool

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Example

Input: 98.6 degrees Fahrenheit (F) to Celsius (C)

Result: 37 C

C = (F - 32) x 5/9 = (98.6 - 32) x 5/9 = 66.6 x 5/9 = 37, the classic normal body temperature.

Temperature Reference Points

CelsiusFahrenheitKelvinWhat it is
-273.15 C-459.67 F0 KAbsolute zero
-40 C-40 F233.15 KWhere C and F meet
-18 C-0.4 F255.15 KTypical home freezer
0 C32 F273.15 KWater freezes
4 C39.2 F277.15 KTypical fridge
20 C68 F293.15 KRoom temperature
37 C98.6 F310.15 KAverage body temperature
100 C212 F373.15 KWater boils (sea level)
180 C356 F453.15 KModerate oven
220 C428 F493.15 KHot oven

Values from this converter, rounded to 4 decimal places.

  1. Select the temperature scale you want to convert from (Celsius, Fahrenheit, Kelvin, or Rankine).
  2. Enter your temperature value in the input field - negative values are supported.
  3. See the result in your chosen target scale, plus the equivalent in every other scale, calculated instantly.
  4. Review the conversion formulas in the Formula section further down the page to understand the math.
  5. Copy the converted temperature you need with a single click on the copy button.
  6. Use this tool for weather conversions, cooking temperatures, or scientific calculations.

How Celsius, Fahrenheit and Kelvin Relate

To convert Celsius to Fahrenheit, multiply by 1.8 and add 32, so 20 C is 68 F. To go back, subtract 32 and divide by 1.8. This converter does the math for Celsius, Fahrenheit, Kelvin and Rankine, and shows all four scales at once.

Temperature is trickier than most units because the scales start at different points. Water freezes at 0 C but at 32 F. It boils at 100 C, or 212 F at sea level. So a 100-degree span in Celsius is a 180-degree span in Fahrenheit. That is where the 1.8 comes from, and the 32 lines up the two freezing points.

For quick weather checks, double the Celsius number and add 30. That turns 20 C into 70 F when the true answer is 68 F. The shortcut is good enough for picking a coat, not for cooking. Ovens need the exact figure. For Gas Mark settings, try the Baking Conversion Calculator.

Kelvin and Rankine are used in science and engineering. Both start at absolute zero, the coldest possible temperature. A kelvin is the same size as a Celsius degree, so you just add 273.15. Rankine uses Fahrenheit-sized degrees instead. Gas law formulas need one of these absolute scales. For those problems, pair this tool with the Pressure Converter.

Formula / How It Works

F = (C x 9/5) + 32 | K = C + 273.15 | R = (C + 273.15) x 9/5 | C = (F - 32) x 5/9

Sources

Frequently Asked Questions

Double the Celsius figure and add 30. For 25 C that gives 80 F, and the exact answer is 77 F. The shortcut is close for everyday weather but drifts further off at high temperatures. For an exact answer, multiply by 1.8 and add 32.
It is 176.67 C. Recipes and oven dials usually round this to 180 C, or 175 C in some books. Other common settings are 400 F (204.4 C) and 425 F (218.3 C). To work these out yourself, subtract 32 and then divide by 1.8.
180 C is exactly 356 F. Many recipes treat 180 C and 350 F as the same oven setting, since a 6-degree gap rarely matters for baking. Fan ovens are often set about 20 C lower than the recipe says, but check the guide that came with your oven.
The two scales meet at -40 degrees. You can check it with the formula: -40 x 1.8 + 32 = -40. It is the only point where both scales show the same number. Above it, the Fahrenheit reading is always the higher of the two.
Absolute zero is the coldest possible temperature. It is 0 K, which is -273.15 C, -459.67 F and 0 R. The Kelvin and Rankine scales both start there, so they never go below zero. Scientists have cooled matter to within a tiny fraction of a degree of it, but never reached it exactly.
Multiply the change by 1.8 and do not add 32. A rise of 5 C is a rise of 9 F. Adding 32 only applies to actual readings, because it shifts the zero point. This tool converts readings, so if you type 5 C it shows 41 F, not the 9 F change.

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