US gallon (gal)

Definition

The US liquid gallon, exactly 231 cubic inches (3.785411784 liters).

History

The US gallon derives from the old English wine gallon of 231 cubic inches, a value the United States kept when Britain moved to a larger imperial gallon in 1824. It equals exactly 3.785411784 liters.

Where it is used

The gallon is the everyday US unit for fuel, milk and paint; the imperial gallon used in the UK and Canada is about 20 percent larger.

Typical uses include fuel in the US, large containers, paint.

Conversion pages

These pages convert US gallon to or from another unit in volume.

• Liter to US gallon

Other Volume units

• Liter (L)
• Milliliter (mL)
• US quart (qt)
• US pint (pt)
• US cup (cup)
• US fluid ounce (fl oz)
• Tablespoon (tbsp)
• Teaspoon (tsp)
• Cubic meter (m³)
• Cubic foot (ft³)

Sources

• NIST HB 44 NIST Handbook 44, Appendix C §2 (U.S. Customary Units) and §5 (Tables of Equivalents) · Dataset reviewed Nov 11, 2026