Common Temperature Units
This converter supports commonly used units including:
- Celsius (°C)
- Fahrenheit (°F)
- Kelvin (K)
- Rankine (°R)
- Réaumur (°Ré)
When to Convert Temperature Units
Temperature conversion is useful for weather, cooking, science, medicine, HVAC, manufacturing, engineering, and laboratory calculations. An online converter helps reduce manual calculation errors and makes it easier to compare values expressed in different units.
Temperature Conversion FAQ
What are the most commonly used temperature units?
The most commonly used temperature units are degrees Celsius (°C), degrees Fahrenheit (°F), and kelvins (K). Rankine (°R) is used in some engineering applications, while Réaumur (°Ré) is mainly historical.
Why is temperature conversion different from most unit conversions?
Temperature scales do not all begin at the same zero point, so conversions may require both multiplication and addition or subtraction. A simple conversion factor is not sufficient for converting between Celsius, Fahrenheit, and Kelvin.
What is the formula for converting Celsius to Fahrenheit?
Use °F = (°C × 9/5) + 32. For example, 20°C converts to 68°F.
What is the formula for converting Fahrenheit to Celsius?
Use °C = (°F − 32) × 5/9. For example, 68°F converts to 20°C.
What is the formula for converting Celsius to Kelvin?
Use K = °C + 273.15. For example, 0°C converts to 273.15 K. Kelvin values are written without a degree symbol.
What is absolute zero?
Absolute zero is the lowest limit of thermodynamic temperature. It equals 0 K, −273.15°C, −459.67°F, and 0°R.
What is the Rankine temperature scale?
Rankine is an absolute temperature scale that uses Fahrenheit-sized intervals. Convert Fahrenheit to Rankine using °R = °F + 459.67, or convert Kelvin to Rankine using °R = K × 9/5.
What is the Réaumur temperature scale?
The Réaumur scale sets the freezing point of water at 0°Ré and its boiling point at 80°Ré under standard conditions. Convert Celsius to Réaumur using °Ré = °C × 4/5.
Are negative Kelvin values valid?
Negative Kelvin values are not used for ordinary thermodynamic temperature. If a standard temperature conversion produces a value below 0 K, the original input is below absolute zero and is outside the normal physical range of the scale.