The liter (L) is the everyday metric unit for liquids such as drinks, fuel and paint. NIST's conversion table gives 1 L = 0.001 cubic meters exactly, which is the same as 1,000 cubic centimeters or 1,000 milliliters.
Conversion
US gallons = L ÷ 3.785412
US fl oz = L × 33.814
US cups = L ÷ 0.236588
mL = L × 1000
Example
A 2 L bottle holds 2 × 33.814 = 67.63 US fluid ounces, or 2 ÷ 3.785412 = 0.528 US gallons. A 0.75 L bottle is 750 mL.
The guides how many liters in a gallon and how many ounces in a liter have full charts; the converters liters to gallons and liters to oz take any value.
Common mistakes
Liters measure volume, not weight. Water is close to 1 kg per liter, but oil, milk and honey differ. The gallon comparison also depends on the country: a liter is 0.22 imperial gallons but 0.2642 US gallons.