Temperature Converter

Convert Celsius, Fahrenheit, Kelvin and Rankine with the correct offset formulas. 0 C = 32 F = 273.15 K.

· CalcFlow Editorial

20 °C = 68 °F

Results shown are estimates for informational purposes only. Nothing on CalcFlow is financial, tax, legal, or medical advice. Always consult a qualified professional before making important decisions.

Common Temperature Conversions

CelsiusFahrenheitKelvinRankine
-40 °C-40233.15419.67
-10 °C14263.15473.67
0 °C32273.15491.67
10 °C50283.15509.67
20 °C68293.15527.67
25 °C77298.15536.67
37 °C98.6310.15558.27
100 °C212373.15671.67
180 °C356453.15815.67

Formula

F = C x 9/5 + 32; C = (F - 32) x 5/9; K = C + 273.15; R = F + 459.67

Understanding Temperature Conversion

Temperature scales do not share a zero point, so converting between them needs an offset as well as a multiplier. Celsius sets 0 at the freezing point of water and 100 at its boiling point at standard pressure. Fahrenheit sets those at 32 and 212. Kelvin starts at absolute zero and uses the Celsius degree size, so 0 degrees C is 273.15 K. Rankine starts at absolute zero with the Fahrenheit degree size.

Tips and Best Practices

  • 1Fahrenheit to Celsius: subtract 32, then multiply by 5/9 (about 0.556).
  • 2Celsius to Fahrenheit: multiply by 1.8, then add 32.
  • 3At -40 degrees the Celsius and Fahrenheit scales give the same number.

Real-World Example

A comfortable room at 20 degrees C is 20 x 1.8 + 32 = 68 degrees F. Normal body temperature of 98.6 degrees F is (98.6 - 32) x 5/9 = 37 degrees C.

Common Mistakes to Avoid

  • Multiplying first and forgetting the 32 offset (or applying the offset in the wrong order).
  • Using degrees with Kelvin; the unit is written K, not degrees K.
  • Converting a temperature difference with the offset formula; a 10 degree C change is an 18 degree F change, with no offset.

How to Use

  1. Pick the unit you have in the left selector and the unit you want in the right selector.
  2. Type a number in either box; the other box updates instantly.
  3. Use the swap button to reverse the direction and Copy result to copy the answer.

Frequently Asked Questions

Q

What is 0 degrees Celsius in Fahrenheit?

0 degrees Celsius is exactly 32 degrees Fahrenheit, the freezing point of water.
Q

How do I convert Celsius to Kelvin?

Add 273.15 to the Celsius value. 25 degrees C is 298.15 K.
Q

At what temperature are Celsius and Fahrenheit equal?

At -40. That is the only temperature where both scales read the same number.

Sources: BIPM SI Brochure (kelvin, triple point and Celsius offset 273.15); NIST SP 811 (Fahrenheit and Rankine definitions).