There are approximately 4.227 US customary cups in one liter. One US cup equals 236.588 mL. In cooking, a liter is often rounded to about 4 cups, but for precise recipes it is best to use milliliters.

A US gallon equals 3.785 liters, while a UK (imperial) gallon equals 4.546 liters. This means a UK gallon is about 20% larger. Fuel economy figures (miles per gallon) cannot be compared directly between US and UK contexts without this adjustment.

One US fluid ounce equals approximately 29.574 mL. A 12 fl oz can of soda contains about 355 mL. The UK fluid ounce is slightly different at 28.413 mL. Always check which country's standard applies when working with recipes or product specifications.

One US tablespoon equals exactly 14.787 mL, often rounded to 15 mL in recipes. There are 3 teaspoons per tablespoon and 16 tablespoons per US cup. Australian tablespoons are 20 mL, so recipes from different countries can differ if you don't check the standard.

Liters are practical for everyday liquid volumes — beverages, fuel, water consumption, and cooking. Cubic meters are used for large-scale volumes such as concrete, water tanks, shipping containers, and gas volumes. One cubic meter equals exactly 1,000 liters.