Convert between metric and imperial units for length, weight, temperature, area, volume, and speed. Your result updates automatically as you type.
Most units are converted through one base unit, like metres for length or kilograms for weight, using a fixed number to multiply by.
Temperature is different. It needs both a scale change and a number added or subtracted, because the zero points of the two scales are not the same.
Standard conversion: Value × conversion factor
Celsius to Fahrenheit: (°C × 9 ÷ 5) + 32
Celsius to Kelvin: °C + 273.15
Why does temperature need a different formula?
Length and weight scales all start from zero, so one multiplication is enough. But Celsius and Fahrenheit start from different points, so we also need to add or subtract a number, not just multiply.
How accurate are these conversions?
They use the official, internationally agreed conversion numbers, so they are exact for units like inches to centimetres. The result is only rounded when it is shown on screen.