As an American, you encounter both metric and imperial units every day—whether you're buying groceries, planning a road trip, or following a recipe from another country. Here are the most essential conversions you need to know.
Length Conversions
Americans use inches, feet, and miles for most everyday measurements, but you'll often see centimeters and meters too—especially when shopping online or traveling.
| Metric | Imperial | Conversion Factor |
|---|---|---|
| 1 centimeter (cm) | 0.3937 inches | Divide by 2.54 |
| 1 meter (m) | 3.2808 feet | Multiply by 3.28 |
| 1 kilometer (km) | 0.6214 miles | Multiply by 0.621 |
Weight Conversions
Pounds rule in the US for body weight and food, but kilograms are standard in many other countries and in scientific contexts.
| Metric | Imperial | Conversion Factor |
|---|---|---|
| 1 kilogram (kg) | 2.2046 pounds (lb) | Multiply by 2.205 |
| 1 gram (g) | 0.0353 ounces (oz) | Multiply by 0.0353 |
Temperature Conversions
Fahrenheit is the standard in the US for weather and cooking, but Celsius is used worldwide.
Formula: (°F - 32) × 5/9 = °C
Common reference points:
- Freezing: 32°F = 0°C
- Room temp: 68°F = 20°C
- Boiling: 212°F = 100°C
- Normal body temp: 98.6°F = 37°C
Volume Conversions
US gallons and cups are different from their metric counterparts—and even from UK measurements!
| Metric | US Imperial | Conversion Factor |
|---|---|---|
| 1 liter (L) | 0.2642 US gallons | Multiply by 0.264 |
| 1 milliliter (mL) | 0.0338 fluid ounces (fl oz) | Multiply by 0.0338 |
Quick Tips for Everyday Use
- Shopping online: Most international retailers list sizes in centimeters. Use our length converter to find your US size.
- Cooking: European recipes often use grams and milliliters. Keep our weight and volume converters handy.
- Traveling: Road signs in Canada and Mexico use kilometers. Convert miles to km using our speed converter.
- Weather: When checking international weather, convert Celsius to Fahrenheit using our temperature converter.
Related Tools
FAQ
Why does the US use imperial units?
The US adopted the British imperial system before the metric system was standardized. While metric is used in science and international trade, everyday life still relies on customary units.
Are US gallons the same as UK gallons?
No! A US gallon is 3.785 liters, while a UK (imperial) gallon is 4.546 liters. Always specify which gallon you're referring to.
What's the easiest way to convert units?
Use UnitFig's free online converters for accurate, instant results. No math required!