Unit Converter
Quick conversions between measurement units
Same value in every length unit
All Unit Converter Categories
Fast and accurate unit conversions for length, weight, temperature, area, and more. Pick a category below to jump straight to a dedicated converter.
Popular Unit Conversions
Explore popular conversions for quick and accurate results.
Length Unit Converters
Explore length conversions including meters to feet, kilometers to miles, inches to centimeters, and more for quick and accurate results.
Weight & Mass Unit Converters
Explore weight conversions including kilograms to pounds, grams to ounces, tons to kilograms, and more for fast, accurate results.
Temperature Unit Converters
Convert temperature units online — Celsius to Fahrenheit, Kelvin, and more.
Volume Unit Converters
Explore volume conversions including liters, gallons, cubic meters, milliliters, cubic feet, cups, pints, and more for fast, accurate results every time.
Area Unit Converters
Explore area conversions including square meters, square feet, acres, hectares, and square miles for fast, accurate results.
Time Unit Converters
Explore time conversions including seconds, minutes, hours, days, and weeks for fast, accurate results.
Unit Converter: Convert Length, Weight, Temperature, Area, Volume & Time
This free unit converter changes a measurement from one unit to another instantly. Choose a category, pick the units, type a value and the result updates as you type. The same value is also shown in every other unit of that category, so one entry can answer several questions at once. It covers the metric system, imperial units and US customary units, and it works on any device.
Quick answer: 1 mile is 1.609344 kilometers, 1 kilogram is about 2.2046 pounds, 0 °C is 32 °F, and 1 US gallon is 3.785412 liters. For anything else, pick a category above and enter your value.
How Unit Conversion Works
Most conversions multiply by a fixed factor. To convert a length from miles to kilometers you multiply by 1.609344, and to go back you divide by it. The converter does this by changing your value to a base unit (meters, square meters, liters, kilograms or seconds) and then into the unit you chose. That keeps every combination accurate, including unusual ones like acres to square feet.
These exact values are the ones used most often:
| Unit | Equals |
|---|---|
| 1 inch | 2.54 centimeters |
| 1 foot | 0.3048 meters |
| 1 mile | 1.609344 kilometers |
| 1 pound | 0.45359237 kilograms |
| 1 ounce | 28.349523 grams |
| 1 US gallon | 3.785412 liters |
| 1 acre | 4,046.8564 square meters |
| 1 hectare | 10,000 square meters |
| 1 day | 86,400 seconds |
Temperature Conversion
Temperature is the exception, because the scales start at different zero points, so you add or subtract as well as multiply.
For example, 25 °C is 77 °F and 298.15 K. The converter will not accept values below absolute zero (−273.15 °C), because nothing can be colder. If you only need temperatures, the temperature converter is a quicker page.
US, Imperial and Metric Units
Some units share a name but not a size. A US gallon is 3.785412 liters, while an imperial (UK) gallon is 4.54609 liters, so the converter lists them separately. The same applies to cups and fluid ounces. Month and year are shown as averages (30.44 and 365.25 days) because calendar months and years vary in length.
Specific Converters
For a closer look at one type of unit, use the dedicated pages: the length converter, the weight converter, the volume converter, the area converter and the speed converter. They have extra units, tables and examples for that category. For sums that involve areas or volumes, the area calculator and the density calculator are useful companions.
Who Uses a Unit Converter?
Students use it for science and math homework, cooks and bakers use it to scale recipes, travelers use it for distances, speeds and temperatures, and builders and engineers use it for materials and measurements. Because results are shown to 8 significant digits, it is also precise enough for most technical work.
How to Use This Unit Converter
Choose a measurement type
Pick length, temperature, area, volume, weight or time.
Enter the value
Type the number you want to convert.
Pick your units
Choose the starting unit and the target unit, or use the swap button.
Read the result
The answer appears instantly, with the formula and the value in every other unit.