Unit Converter
Convert length, weight, and temperature units.
About Unit Converter
Convert between metric and imperial units instantly with this free online unit converter for length, weight, and temperature. Switch between millimeters, meters, and miles; grams, kilograms, and pounds; or Celsius, Fahrenheit, and Kelvin, all with exact standard conversion factors and results trimmed to the precision you need. It works entirely offline in your browser once loaded, so it's quick and private with no ads getting in the way of the answer. Whether you're cooking, traveling, doing homework, or working on an engineering problem, you get an accurate conversion the moment you type a value.
How to use this tool
- 1Pick a category: length, weight, or temperature.
- 2Enter a value and choose the unit you're converting from.
- 3Choose the unit you're converting to and see the result instantly.
Everyday conversion factors worth memorizing
A few conversion factors cover most day-to-day needs. These are the exact or near-exact values this converter uses.
| From | To | Multiply by |
|---|---|---|
| Inches | Centimeters | 2.54 (exact) |
| Miles | Kilometers | 1.60934 |
| Pounds | Kilograms | 0.45359 |
| Ounces | Grams | 28.3495 |
| US gallons | Liters | 3.78541 |
| Fahrenheit | Celsius | (°F − 32) × 5⁄9 |
Handy approximations: a kilometer is about 0.6 miles, a kilogram is about 2.2 pounds, and room temperature (20-22 °C) is 68-72 °F. For precise work, always use the full-precision converter above rather than mental shortcuts.
Frequently asked questions
Which unit categories are supported?
Length (mm to miles), weight (mg to pounds), and temperature (Celsius, Fahrenheit, Kelvin).
How precise are the results?
Conversions use exact standard factors and are shown to high precision, trimming trailing zeros.