Tools To India

Temperature Converter

Convert a temperature between the three scales. Values below absolute zero are rejected rather than silently converted.

Last updated

The result updates as you type. Nothing you enter is saved, sent to a server or shared.

37°C equals

98.6°F

The same temperature on all three scales

Celsius
37°C
Fahrenheit
98.6°F
Kelvin
310.15K

Reference points

Water freezes
0°C · 32°F · 273.15 K
Normal human body temperature
37°C · 98.6°F · 310.15 K
Water boils at sea level
100°C · 212°F · 373.15 K
Absolute zero
−273.15°C · −459.67°F · 0 K

How this calculator works

Temperature is the one common conversion that cannot be done with a simple multiplication, because the scales do not share a zero point. Celsius puts zero at the freezing point of water, Fahrenheit puts it 32 degrees lower, and Kelvin puts it at absolute zero.

That means every conversion needs both a scale factor and an offset. Celsius and Kelvin share the same degree size, so converting between them is only an offset of 273.15. Fahrenheit degrees are five-ninths the size of Celsius degrees, so that conversion needs both.

The two scales cross at −40, where Celsius and Fahrenheit give the same number. It is a genuinely useful fact for checking that a conversion has been done correctly.

Kelvin has no degree symbol and no negative values, because it starts at absolute zero — the point at which a system has minimum thermal energy. This calculator rejects any input that would fall below it.

The formula

Celsius to Fahrenheit

°F = (°C × 9 ÷ 5) + 32

Fahrenheit to Celsius

°C = (°F − 32) × 5 ÷ 9

Celsius to Kelvin

K = °C + 273.15

The degree size is identical, so this is a pure offset. Kelvin is written without a degree symbol.

Worked example: normal body temperature

Converting 37°C, the standard reference for normal human body temperature.

Step-by-step calculation for the worked example
Starting value37°C
Multiply by 9 ÷ 566.6
Add 3298.6°F
To Kelvin: add 273.15310.15 K
A fever of 101°F back to Celsius38.3°C

37°C is 98.6°F, the familiar figure for normal body temperature. A reading of 101°F, commonly treated as a fever, is 38.3°C.

Things worth knowing

  • Kelvin takes no degree symbol. Write 310.15 K, not 310.15 °K.
  • Absolute zero is −273.15°C. Nothing can be colder, so this calculator rejects such inputs rather than producing a meaningless number.
  • −40 is the same on the Celsius and Fahrenheit scales. It is a quick way to check a conversion.
  • A temperature difference converts differently from a temperature. A rise of 10°C is a rise of 18°F, not 50°F, because the offset does not apply to differences.
  • India uses Celsius for weather, medicine and everyday life. Fahrenheit appears mainly in older medical thermometers and in content from the United States.

Frequently asked questions

How do I convert Celsius to Fahrenheit quickly?
Multiply by 9, divide by 5, then add 32. For a rough mental estimate, double the Celsius figure and add 30 — that gives 34 for 2°C where the exact answer is 35.6, close enough for weather.
What is normal body temperature?
37°C, or 98.6°F, is the conventional reference, though normal readings vary between roughly 36.1°C and 37.2°C depending on the person, the time of day and how it is measured.
Why does Kelvin not use a degree symbol?
Because it is an absolute scale rather than a relative one. It measures from absolute zero, so a Kelvin value is a quantity rather than a position on an arbitrary scale. The SI convention is to write "310 K" without the degree sign.
Is a 10-degree rise the same in both scales?
No. A rise of 10°C is a rise of 18°F, because a Fahrenheit degree is smaller. When converting a difference rather than a temperature, apply only the 9/5 factor and not the 32-degree offset.

Sources

Every figure on this page is traceable to the official source below. If a source has changed since the date shown, please tell us and we will correct it.