A gallon calculator converts between US gallons and 30+ volume units including liters, cups, quarts, fluid ounces, and cubic feet. Includes US vs Imperial gallon comparison.
A gallon (gal) is a unit of volume used in the United States and United Kingdom. There are two types:
The Imperial gallon is 20.1% larger than the US gallon. Always specify which gallon you mean to avoid errors.
Key US gallon conversions:
= 3.785 L = 128 fl oz = 16 cups = 4 quarts = 8 pints = 231 in³.
= 18.93 L = 640 fl oz = 80 cups = 0.669 ft³.
= 4.546 L = 1.201 US gallons = 160 Imp fl oz.
= 208.2 L = 12,705 in³ = 7.35 ft³.
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Answers to common questions about the gallon calculator.
1 US gallon = 3.78541 liters. 1 Imperial gallon = 4.54609 liters. The Imperial gallon is about 20% larger than the US gallon.
16 US cups = 1 US gallon. 1 cup = 236.59 mL. So 16 × 236.59 = 3,785.4 mL = 3.785 L = 1 US gallon.
128 US fluid ounces = 1 US gallon. 160 Imperial fluid ounces = 1 Imperial gallon. US and Imperial fluid ounces are slightly different sizes.
Multiply by 0.13368. 1 gallon = 0.13368 ft³. 7.481 gallons = 1 ft³. 100 gallons = 13.37 ft³.
The US gallon (231 in³) was defined by the 1707 Wine Gallon. The Imperial gallon (277.42 in³) was defined in 1824 as the volume of 10 pounds of water. They diverged historically and were never reconciled.