Unit Conversion Calculators

These converters bridge the gap between the metric system used by most of the world and the customary units used in the United States. Whether you are reading an international product label, following a forecast in Celsius, or planning a trip measured in kilometers, each tool uses the exact, internationally defined conversion factor and includes a quick-reference table for common values.

Weight: Kilograms and Pounds

The pound is defined as exactly 0.45359237 kilograms, so weight conversions are precise rather than approximate. Going from kilograms to pounds you multiply by about 2.205; going the other way you divide by the same figure. These come up constantly with body weight, luggage allowances, and shipping. See the Kilograms to Pounds and Pounds to Kilograms calculators.

Distance: Kilometers and Miles

One mile equals exactly 1.609344 kilometers. Distance conversions are purely proportional, which makes them straightforward for road signs, race lengths, and maps. Runners in particular meet these numbers at every metric race distance. Try the Kilometers to Miles and Miles to Kilometers calculators.

Temperature: Celsius and Fahrenheit

Temperature is the one conversion in this group that is not a simple multiplication, because the two scales start at different points. You rescale the degree size with a 9/5 or 5/9 factor and adjust for the 32-degree offset. The Celsius to Fahrenheit and Fahrenheit to Celsius calculators handle both directions and explain why the order of steps matters.

All calculators provide estimates for educational purposes only. See our Financial Disclaimer and Methodology.