CalcKit
Temperature Converter
Table of Contents
Definition of Temperature
Temperature measures how hot or cold something is; in physics, it reflects the average energy of motion of its particles. Most scales are set by two fixed points, usually the freezing and boiling points of water, while the Kelvin and Rankine scales start at absolute zero.
Celsius is used in most of the world, Fahrenheit in the United States, and Kelvin in science. The Delisle, Newton, Réaumur and Rømer scales are historical.
How to convert temperatures
Type a value into any field, and every other scale is calculated at once. A temperature scale has a zero point as well as a degree size, so a conversion multiplies and then adds the offset. For example, a room at 25 °C:
-
In °F: multiply by 9/5, then add 32.
25 * 9 / 5 + 32 = 77 °F -
In kelvin: add 273.15.
25 + 273.15 = 298.15 K
The other way round, a body temperature of 98.6 °F is (98.6 - 32) * 5 / 9 = 37 °C.
A temperature difference, such as a rise of 10 degrees, converts without the offset: a rise of 10 °C is a rise of 18 °F. Differences are converted in the Temperature Interval Converter.
Common temperatures
| Celsius | Fahrenheit | Kelvin | |
|---|---|---|---|
| Absolute zero | -273.15 °C | -459.67 °F | 0 K |
| Celsius equals Fahrenheit | -40 °C | -40 °F | 233.15 K |
| Water freezes | 0 °C | 32 °F | 273.15 K |
| Room temperature | 20 °C | 68 °F | 293.15 K |
| Body temperature | 37 °C | 98.6 °F | 310.15 K |
| Water boils (at sea level) | 100 °C | 212 °F | 373.15 K |
| Oven, moderate | 177 °C | 350 °F | 450 K |
Temperature Units
Celsius (°C)
The Celsius scale, also known as the centigrade scale, is widely used in most parts of the world. It defines the freezing point of water at 0°C and the boiling point at 100°C, under standard atmospheric pressure.
Conversion Factors:
- Celsius to Fahrenheit:
°F = °C * 9/5 + 32 - Celsius to Kelvin:
K = °C + 273.15 - Celsius to Rankine:
°R = °C * 9/5 + 32 + 459.67 - Celsius to Delisle:
°De = (100 - °C) * 3/2 - Celsius to Newton:
°N = °C * 33/100 - Celsius to Réaumur:
°Ré = °C * 0.8 - Celsius to Rømer:
°Rø = °C * 21/40 + 7.5
Fahrenheit (°F)
The Fahrenheit scale is commonly used in the United States, and some other countries. It sets the freezing point of water at 32°F and the boiling point at 212°F, under standard atmospheric pressure.
Conversion Factors:
- Fahrenheit to Celsius:
°C = (°F - 32) * 5/9 - Fahrenheit to Kelvin:
K = (°F - 32) * 5/9 + 273.15 - Fahrenheit to Rankine:
°R = °F + 459.67 - Fahrenheit to Delisle:
°De = (212 - °F) * 5/6 - Fahrenheit to Newton:
°N = (°F - 32) * 11/60 - Fahrenheit to Réaumur:
°Ré = (°F - 32) * 4/9 - Fahrenheit to Rømer:
°Rø = (°F - 32) * 7/24 + 7.5
Kelvin (K)
The Kelvin scale is the SI unit of temperature and is commonly used in scientific and engineering applications. It is based on the absolute zero, the lowest possible temperature, defined as 0 Kelvin (-273.15°C).
Conversion Factors:
- Kelvin to Celsius:
°C = K - 273.15 - Kelvin to Fahrenheit:
°F = (K - 273.15) * 9/5 + 32 - Kelvin to Rankine:
°R = K * 9/5 - Kelvin to Delisle:
°De = (373.15 - K) * 3/2 - Kelvin to Newton:
°N = (K - 273.15) * 33/100 - Kelvin to Réaumur:
°Ré = (K - 273.15) * 4/5 - Kelvin to Rømer:
°Rø = (K - 273.15) * 21/40 + 7.5
Rankine (°R)
The Rankine scale is primarily used in engineering, especially in the United States, and is based on the Fahrenheit scale. Absolute zero is defined as 0 Rankine.
Conversion Factors:
- Rankine to Celsius:
°C = (°R - 491.67) * 5/9 - Rankine to Fahrenheit:
°F = °R - 459.67 - Rankine to Kelvin:
K = °R * 5/9 - Rankine to Delisle:
°De = (671.67 - °R) * 5/6 - Rankine to Newton:
°N = (°R - 491.67) * 11/60 - Rankine to Réaumur:
°Ré = (°R - 491.67) * 4/9 - Rankine to Rømer:
°Rø = (°R - 491.67) * 7/24 + 7.5
Delisle (°De)
The Delisle scale was developed by Joseph-Nicolas Delisle, a French astronomer. It is based on the concept of "reversed Celsius", where the boiling point of water is 0°De, and the freezing point is 150°De.
Conversion Factors:
- Delisle to Celsius:
°C = 100 - (°De * 2/3) - Delisle to Fahrenheit:
°F = 212 - (°De * 6/5) - Delisle to Kelvin:
K = 373.15 - (°De * 2/3) - Delisle to Rankine:
°R = 671.67 - (°De * 6/5) - Delisle to Newton:
°N = 33 - °De * 11/50 - Delisle to Réaumur:
°Ré = 80 - °De * 8/15 - Delisle to Rømer:
°Rø = 60 - °De * 7/20
Newton (°N)
The Newton scale, proposed by Sir Isaac Newton, is based on dividing the range between the freezing and boiling points of water into 33 equal parts.
Conversion Factors:
- Newton to Celsius:
°C = °N * 100/33 - Newton to Fahrenheit:
°F = °N * 60/11 + 32 - Newton to Kelvin:
K = °N * 100/33 + 273.15 - Newton to Rankine:
°R = °N * 60/11 + 491.67 - Newton to Delisle:
°De = (33 - °N) * 50/11 - Newton to Réaumur:
°Ré = °N * 80/33 - Newton to Rømer:
°Rø = °N * 35/22 + 7.5
Réaumur (°Ré)
The Réaumur scale, developed by René Antoine Ferchault de Réaumur, sets the freezing point of water at 0°Ré and the boiling point at 80°Ré.
Conversion Factors:
- Réaumur to Celsius:
°C = °Ré * 5/4 - Réaumur to Fahrenheit:
°F = °Ré * 9/4 + 32 - Réaumur to Kelvin:
K = °Ré * 5/4 + 273.15 - Réaumur to Rankine:
°R = °Ré * 9/4 + 491.67 - Réaumur to Delisle:
°De = (80 - °Ré) * 15/8 - Réaumur to Newton:
°N = °Ré * 33/80 - Réaumur to Rømer:
°Rø = (°Ré * 21/32) + 7.5
Rømer (°Rø)
The Rømer scale, developed by Ole Rømer, a Danish astronomer, sets the freezing point of water at 7.5°Rø and the boiling point at 60°Rø.
Conversion Factors:
- Rømer to Celsius:
°C = (°Rø - 7.5) * 40/21 - Rømer to Fahrenheit:
°F = (°Rø - 7.5) * 24/7 + 32 - Rømer to Kelvin:
K = (°Rø - 7.5) * 40/21 + 273.15 - Rømer to Rankine:
°R = (°Rø - 7.5) * 24/7 + 491.67 - Rømer to Delisle:
°De = (60 - °Rø) * 20/7 - Rømer to Newton:
°N = (°Rø - 7.5) * 22/35 - Rømer to Réaumur:
°Ré = (°Rø - 7.5) * 32/21