If you’ve ever had to match American and metric measurement units, you know direct comparisons of these unit systems can be tricky. If you need to know the metric equivalent of an inch, for example, or the American equivalent of a kilometer, use the following table to help you make a proper comparison between the two systems of measurement.
| American Length | Metric Length |
| * | millimeter |
| inch | centimeter (0.4 inches) |
| foot (12 inches) | * |
| yard (3 feet) | meter (39.37 inches) |
| rod (16.5 feet) | * |
| furlong (1/8 mile) | * |
| mile (5,280 feet) | kilometer (0.6214 miles) |
| American Area | Metric Area |
| square inch | square centimeter (0.1550 square inches) |
| square foot (144 square inches) | square decimeter (0.1076 square feet) |
| square yard (9 square feet) | * |
| acre (43,560 square feet) | hectare (10,000 square meters, 0.01 square kilometers, 0.4047 acres) |
| square mile (640 acres) | square kilometer (0.3861 square miles) |
| American Volume | Metric Volume |
| * | cubic millimeter |
| cubic inch | cubic centimeter (0.0610 cubic inches) |
| cubic foot (1,728 cubic inches) | cubic meter (0.0283 cubic feet) |
| cubic yard (27 cubic feet) | cubic meter (0.7645 cubic yards) |
| American Weight | Metric Weight |
| * | gram |
| grain | * |
| dram (27.3438 grains) | * |
| ounce (437.5 grains) | * |
| pound (16 ounces, 7,000 grains) | * |
| * | kilogram (1,000 grams) |
| hundredweight (100 pounds) | * |
| ton (20 hundred weight, 2,000 pounds) | tonne (1,000 kilograms, 1.1023 tons) |
| long hundredweight (112 pounds) | * |
| long ton (20 long hundredweight, 2,240 pounds) | * |
| American liquid volume | Metric liquid volume |
| * | milliliter |
| fluid ounce (29.5735 milliliters) | * |
| cup (8 fluid ounces) | * |
| pint (16 fluid ounces) | * |
| * | liter (1,000 milliliters, 1.0567 quarts) |
| quart (32 fluid ounces, 2 pints) | * |
| gallon (4 quarts) | * |
| American Temperature | Metric temperature |
| degrees Fahrenheit | degrees Kelvin |
