This gallons to liters converter turns US gallons into liters as you type, and covers the UK gallon from the same page. It is the conversion for aquariums, water jugs, drums, fuel cans and water heaters sold by the gallon when you think, or calculate, in liters. It runs in your browser and spends no credits.
How many liters are in a gallon
One US gallon is exactly 3.785411784 liters, usually rounded to 3.785 l. It is the US customary gallon, made of 4 quarts, 8 pints or 128 US fluid ounces. The UK gallon is a different unit of 4.54609 liters, explained below.
Gallons to liters formula
Multiply the gallons by 3.785411784:
l = US gal × 3.785411784
Multiplying by 4 is a quick upper bound: 15 gallons × 4 = 60 l, while the exact answer is 56.78 l. The shortcut overshoots by about 5.7 percent.
US gallons to liters table
| US gallons | Liters |
|---|---|
| 0.5 gal | 1.8927 l |
| 1 gal | 3.7854 l |
| 2 gal | 7.5708 l |
| 5 gal | 18.9271 l |
| 10 gal | 37.8541 l |
| 12 gal | 45.4249 l |
| 15 gal | 56.7812 l |
| 20 gal | 75.7082 l |
| 40 gal | 151.4165 l |
| 50 gal | 189.2706 l |
| 55 gal | 208.1976 l |
| 100 gal | 378.5412 l |
| 1,000 gal | 3,785.4118 l |
Worked example: an aquarium and a water jug
A 20 gallon fish tank holds 20 × 3.785411784 = 75.71 liters of water, the number you need when a water conditioner doses per liter. The common 5 gallon water cooler jug holds 18.93 l, just under 19 liters. A 55 gallon drum comes to 208.20 l.
US gallon vs UK gallon
The imperial gallon used in the UK is 4.54609 liters, about 20 percent larger than the US gallon. One US gallon is 0.8327 UK gallons. So 5 UK gallons is 22.73 l, not 18.93 l. If a volume, or a fuel economy figure, comes from a British source, pick UK gallon in the unit list before converting.
FAQ
How many liters is a half gallon of milk?
1.89 liters, for a US half gallon.
How many liters in a quart?
A US quart is a quarter of a US gallon, 0.9464 l. Pick quart in the first list to convert it directly.
What does it cost?
It comes with the Nexin library: Nexin Lite or Nexin Pro opens it, and it spends no credits.
