Free, no signup needed: pick a category, choose your from and to units, and enter a value below to convert instantly.
Result: —
This unit converter covers meters, feet, inches, kilometers, and miles for length; kilograms, pounds, ounces, and grams for weight; and liters, gallons, cups, and more for volume, so you get an exact conversion instead of doing the math by hand. That’s handy for recipes, DIY projects, travel, or double-checking a spec sheet.
How to Use
- Pick a category: length, weight, or volume.
- Choose your from and to units.
- Enter a value to convert.
Example (length): convert 5 kilometers to miles by picking length, setting from to km and to to mi, entering 5, and the tool returns 3.1069 mi.
Example (weight): convert 2 kilograms to pounds by picking weight, setting from to kg and to to lb, entering 2, and the tool returns 4.4092 lb.
Common Conversions at a Glance
A few reference points that come up often enough to memorize.
| Convert | Equals |
|---|---|
| 1 inch | 2.54 cm |
| 1 mile | 1.609 km |
| 1 pound | 453.6 g |
| 1 kilogram | 2.205 lb |
| 1 US gallon | 3.785 liters |
| 1 cup | 240 ml |
Did You Know?
Unit mix-ups aren’t just a kitchen problem. In 1999, NASA lost the $125 million Mars Climate Orbiter because one engineering team calculated thruster force in pounds while the software that read the data assumed metric newtons. The spacecraft entered Mars’s atmosphere at the wrong altitude and was destroyed (source).
Frequently Asked Questions
What units does this converter support?
Length: millimeters, centimeters, meters, kilometers, inches, feet, yards, and miles. Weight: milligrams, grams, kilograms, ounces, and pounds. Volume: milliliters, liters, teaspoons, tablespoons, cups, pints, quarts, and gallons.
How accurate are these conversions?
Results are calculated to four decimal places using standard conversion factors, accurate enough for cooking, home projects, or general reference.
Can I convert between categories, like weight to volume?
No. Weight and volume aren’t directly convertible without knowing the density of what you’re measuring, so each category (length, weight, volume) converts within itself only.
Why does a US cup differ from a metric cup?
A US cup is legally defined as 240 ml, while some countries use a 250 ml metric cup. This tool uses the US cup measurement.
What if I need a unit that isn’t listed?
This tool covers the units people convert most often. More categories, like temperature or speed, may be added over time, so check back if what you need isn’t here yet. For now, a general web search for a rarer conversion factor will get you there quickly.