Unit Converter

How to use Unit Converter

Choose a category and a pair of units. Negative temperatures and decimals are supported. Results use floating-point arithmetic and display up to 10 significant digits.

Convert measurements within one category

Select Length, Weight or Temperature, enter a value, then choose the source and destination units. One inch equals 2.54 cm; one pound equals 0.45359237 kg. These conversions use fixed factors and the displayed precision is limited to keep the result readable.

Temperature uses offsets as well as scale

Unlike length, temperature conversion cannot be done with a single multiplier. Celsius to Fahrenheit uses C × 9/5 + 32, so 20 °C equals 68 °F. Celsius to Kelvin adds 273.15, so 0 °C equals 273.15 K. Values below absolute zero are rejected.

Check what a unit label means

Weight here uses ordinary avoirdupois pounds and ounces, not troy ounces used for precious metals. Feet are international feet. This calculator does not convert volume, area or recipe ingredients; converting a volume to a mass requires a material’s density.

Do you upload my data?

This tool runs in your browser. Inputs and results are not sent to our server. Closing or refreshing the page clears your work, so save any results you need.