Convert Gallons to Liters (gal to L)

1 US gallon is defined as exactly 3.785411784 liters. This calculator uses the US gallon; the UK imperial gallon (about 4.546 L) is a different, larger unit not covered here.

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Result

3.7854L

L → gal

Common conversions

Common US gallon sizes for fuel tanks and containers and their exact liter equivalents.

US Gallons (gal)Liters (L)
1 gal3.79 L
5 gal18.93 L
10 gal37.85 L
15 gal56.78 L
20 gal75.71 L
25 gal94.64 L
30 gal113.56 L
50 gal189.27 L

Rounded for readability. Use the converter above for exact decimals.

How it works

This direction is for when you already have a volume in US gallons — a US car's fuel tank size, a water jug, a home-brewing batch — and need it in liters for a metric context: filling up abroad, following a metric recipe, or comparing against a European product spec.

Renting a car abroad is the case that trips up the most travelers: someone used to thinking in US gallons from home needs to understand liters at a foreign pump. A 15-gallon US tank converts to about 56.8 L, so budgeting for a fill-up in Europe means estimating cost per liter rather than per gallon — multiplying the local price per liter by 56.8 gives a rough total.

Bulk water and beverage containers in the US are commonly sold in 1-gallon and 5-gallon sizes: a 5-gallon water cooler jug converts to about 18.93 L, useful when comparing against a European water delivery service that bills by the liter rather than the gallon.

US fuel economy is quoted in miles per US gallon, which is not the same figure as a UK car's miles per (imperial) gallon — a US-rated 30 mpg and a UK-rated 30 mpg differ by about 17% in actual fuel efficiency, since the imperial gallon (4.546 L) is larger than the US gallon (3.785 L) this calculator converts.

Paint is bought by the container, and the containers differ. A US gallon can holds 3.785 L, so it is about one and a half of the 2.5 L tins sold in metric markets, and a 5 gallon bucket is 18.93 L rather than the 20 L drum it resembles on the shelf. Coverage moves with it: a paint claiming roughly 350 square feet per gallon is claiming about 32.5 m² from 3.785 L, which is the figure to set against a tin labelled in square metres per litre.

Frequently asked questions

How many liters is 1 gallon?
1 US gallon equals exactly 3.785411784 liters — the defined value for the US gallon, not the larger UK imperial gallon (about 4.546 L).
How do I convert gallons to liters without a calculator?
Multiply the gallon value by 3.8 for a close estimate. For example, 15 gal × 3.8 = 57, close to the exact 56.78 L.
I'm renting a car with a 15-gallon tank in Europe — roughly how many liters will I need to fill it?
A 15-gallon US tank holds about 56.78 L. If the tank is close to empty, budget for roughly 57 L at the local price per liter, keeping in mind the car's actual tank size may differ slightly from a nominal "15-gallon" figure.
Is a US gallon the same as a UK (imperial) gallon?
No, and this is a common point of confusion. The US gallon is exactly 3.785411784 L, while the UK imperial gallon is about 4.546 L — roughly 20% larger. This calculator converts the US gallon only; a UK imperial gallon figure would need a different, larger factor.

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Last updated: 2026-08-22

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