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Convert gal to l
1 gal = 3.785411784 l
Type a value in US gallons and the answer in litres appears as you go. The conversion is exactly 3.785411784 l to the us gallon, and it happens on your own machine — this page asks nothing of a server once it has loaded.
Where it runs
In your browser. The number you type is never part of a request.
Exact by definition
1 gal is exactly 3.785411784 l — a definition, not a rounded factor.
Answers as you type
No button, no wait. The worked answer is already on the page before any script runs.
US gallon and Litre
A US gallon is defined as 231 cubic inches, exactly — a definition that comes from an English wine gallon of 1707. The imperial gallon is 4.55 litres, about 20% larger.
A litre is a thousand cubic centimetres. It is not strictly an SI unit — the SI unit of volume is the cubic metre — but it is accepted for use with SI and is what fuel, drinks and engines are measured in.
US gallons to litres in practice
15 gal is 56.78 l
— a US car tank, as the pump measures it.
1 gal is 3.785 l
— a large bottle of milk, as a US shop sells it.
US gallons to litres at a glance
| gal | l |
|---|---|
| 1 | 3.785411784 |
| 2 | 7.570823568 |
| 3 | 11.356235352 |
| 5 | 18.92705892 |
| 10 | 37.85411784 |
| 20 | 75.70823568 |
| 50 | 189.2705892 |
| 100 | 378.5411784 |
Every figure here is computed from the same definition the calculator uses, so the table cannot drift away from the answer above it.
Convert gal to l: common questions
How many litres are in a us gallon?
Exactly 3.785411784. One us gallon is 3.785411784 litres, and the box above will do it for any figure you type.
Is this conversion exact, or rounded?
The ratio is exact. It is not a rounded constant typed into a table: it is derived from the definitions of the two units, so it agrees with any other correct converter to as many digits as you care to compare.
Why does another converter show a slightly different number?
Almost always rounding rather than disagreement. Many converters cut the answer to two or four decimals, and some carry a factor that was rounded before the multiplication rather than after. The figures here are computed from the exact definitions and only rounded on the way to the screen.
Where these figures come from
The claims this page makes about volume units are checkable, and these are the documents that settle them.
How this page works
The factor is a constant in the page and the arithmetic is four operations, so nothing is sent anywhere and nothing needs to be. The number you type never leaves the browser — there is no request for it to travel in.