Gallons to Liters
Convert gallons (us) to liters instantly. Free, fast, no signup.
How to use this tool
- Enter gallons (us) in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your liters and the full breakdown beneath it.
Convert gallons (us) to liters instantly. Free, fast, no signup.
Formula
Liters = Gallons (US) × 3.785411784
The US liquid gallon is defined as exactly 231 cubic inches, which converts to exactly 3.785411784 liters.
How it works
Multiply the US gallon value by 3.785411784 to get liters. This factor is derived from the exact definition of the US gallon (231 in³) combined with the precise inch-to-meter relationship (1 inch = 25.4 mm exactly).
Common mistake: Using the imperial (UK) gallon factor of 4.54609 when working with US gallons, or vice versa. A UK recipe calling for 1 gallon of water requires about 4.55 liters, while a US recipe calling for 1 gallon requires only 3.79 liters — a meaningful difference in cooking and chemistry.
Worked example
Convert 1 US gallon to liters
- Start with 1 US liquid gallon.
- Multiply by 3.785411784: 1 × 3.785411784.
- Round to four decimal places: 3.7854.
1 US gallon = 3.7854 liters
Common mistakes to avoid
- Confusing US liquid gallons (3.7854 L) with Imperial gallons (4.5461 L) -- fuel receipts in the UK use Imperial gallons, so applying the US factor understates the liter result.
- Using 4 as the multiplication factor instead of 3.7854, overstating the result by about 5.7% per gallon.
- Reversing the formula -- dividing by 3.7854 converts liters to gallons, not gallons to liters.
Key terms
- US liquid gallon
- Defined as exactly 231 cubic inches, equal to 3.785411784 liters. The everyday gallon used in the United States.
- Liter
- An SI unit of volume equal to 1 cubic decimeter. The standard volume unit in most countries and in science.
- Cubic inch
- A unit of volume in the imperial and US customary systems, equal to the volume of a cube with 1-inch sides. There are 231 cubic inches in a US gallon.
- Imperial gallon
- The UK gallon equal to 4.54609 liters — larger than the US gallon and not used in this conversion.
Frequently asked questions
- How do I convert gallons (us) to liters?
- Multiply the number of gallons (us) by 3.78541 to get liters.