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Calcenta

Gallons to Liters Converter

Convert US gallons to liters instantly, with a reference table for fuel tanks, aquariums and paint.

Gallons to Liters Converter

1 gal = 3.7854 L

Multiply US gallons by 3.78541178 to get liters.

The link carries the values you entered, so whoever opens it sees the same result. Nothing is stored on our side — the numbers travel in the link itself.

US gallons to liters reference table

The conversions people look up most often, rounded to 4 decimal places.

Common US gallons to liters conversions
US gallon (gal)Liter (L)
1 gal3.7854 L
2 gal7.5708 L
3 gal11.3562 L
5 gal18.9271 L
10 gal37.8541 L
15 gal56.7812 L
20 gal75.7082 L
25 gal94.6353 L
30 gal113.5624 L
40 gal151.4165 L
55 gal208.1976 L
75 gal283.9059 L
100 gal378.5412 L

The US gallons people look up most

1 gal = 3.7854 L
The US gallon against the imperial one, which is 4.546 L - a fifth larger, and the reason old British fuel figures never match.
5 gal = 18.9271 L
A US bucket, and the water-cooler bottle size used across North America.
42 gal = 158.9873 L
One barrel of oil, which is a unit of its own and not a gallon multiple anyone chose deliberately.
55 gal = 208.1976 L
The standard American oil drum. Elsewhere the equivalent is a 200 L drum, which holds about eight litres less.

How the gallons to liters calculation works

A US gallon is exactly 3.785411784 liters:

liters = US gallons × 3.785411784

The odd factor is historical. The US gallon was fixed as 231 cubic inches — the volume of an old English wine gallon — while Britain redefined its own gallon in 1824 as the volume of ten pounds of water, giving 4.54609 L. The two have been 20% apart ever since.

So an American "gallon of gas" is 3.785 L, and a British "gallon" in an older context is 4.546 L. This converter uses the US gallon.

Common volumes:

  • 1 gal of milk → 3.79 L
  • 5 gal (a US bucket, a water-cooler bottle) → 18.93 L
  • 20 gal aquarium → 75.71 L
  • 55 gal drum → 208.20 L — the standard oil drum, usually described as a 200 L drum outside the US, which is a different drum
  • 1 barrel of oil is 42 US gallons → 158.99 L

Paint is the domestic case where the difference bites. A US gallon covers roughly 350–400 sq ft; a 5 L European tin covers a comparable area but is not the same quantity. Buying "a gallon" of paint in Europe gets you 5 L, which is 32% more than a US gallon — fine for coverage, misleading for cost comparison.

For a mental estimate, multiply by 4 and take off 5%: 5 gal → 20 → 19 L, against a true 18.93.

Frequently asked questions

Does a gallon of petrol weigh the same as a gallon of water?

No. Petrol is about three quarters the density of water, so a US gallon of it weighs roughly 6.2 lb, or 2.8 kg, against water’s 8.34 lb and 3.79 kg. Diesel is denser again at about 7 lb per US gallon. Volume converts on a fixed factor; weight does not, because it depends entirely on what is in the container.

What is an imperial gallon worth in US gallons?

One imperial gallon is 1.201 US gallons, so the two are 20% apart. The confusing part is that the subdivisions match in count but not in size: eight pints to a gallon in both systems, yet an imperial pint is 568 ml and a US one 473 ml. Any fuel figure, tank rating or recipe from a British source written before the 1990s means the imperial gallon.

What is a dry gallon?

A separate American measure for produce, equal to 4.405 L - about 16% larger than the liquid gallon this converter uses. It survives mostly in the dry quart and dry pint that berries and shelled nuts are sold by, and in bushel and peck figures. Anything poured, including milk, paint and fuel, uses the liquid gallon instead.

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