US Gallons to Liters Converter (gal to L)
1 US gal = 3.785411784 L exactly. Convert US gallons to liters for water heaters, tanks and jugs, with UK gallons alongside and a liter chart.
L = US gal × 3.785411784
US Gallon (gal): The US liquid gallon is defined as exactly 231 cubic inches, which is 3.785411784 liters. It is the gallon used for gasoline, milk and water in the United States.
Liter (L): The liter is the metric unit of volume accepted for use with the SI. Since 1964 it has been defined as exactly one cubic decimeter, which is 1,000 cubic centimeters.
| US Gallon (gal) | Liter (L) |
|---|---|
| 1 | 3.785411784 |
| 5 | 18.92705892 |
| 10 | 37.85411784 |
| 25 | 94.6352946 |
| 50 | 189.2705892 |
| 100 | 378.5411784 |
American appliances, tanks and containers are sized in US gallons, while installation manuals abroad, European spare parts and metric water bills work in liters. Anyone fitting a US water heater, dosing a 10-gallon aquarium with a treatment measured per liter, or reading an American spec sheet in another country needs this direction. The US gallon is fixed at 231 cubic inches, and because the inch is exactly 2.54 cm, one gallon comes to exactly 3.785411784 L.
The first chart adds a UK gallon column, since a British or older Canadian figure for the same tank would be about a sixth smaller in number. The household table covers volumes printed on American products and in US water-efficiency rules, from a single toilet flush to a 50-gallon water heater.
How to use this tool
- Type a value in the US Gallon box to see it in liters, or type in the Liter box to convert the other way.
- Press ⇄ to swap the two units, or Load example for a typical value.
- Check the charts below for common values; for other units, open the Volume converter.
Formula
L = US gal × 3.785411784
US gal = L ÷ 3.785411784
Both factors come from exact definitions: 1 liter = 0.264172052358 US gallons and 1 us gallon = 3.785411784 liters (shown to 12 significant digits).
Example
Two conversions worked with the same factors the converter uses:
12 gal × 3.785411784 ≈ 45.4249 L
40 L × 0.264172052358 ≈ 10.5669 gal
US Gallon to Liter chart
Common values from US gallons to liters, rounded to four decimal places.
| US Gallon (gal) | Liter (L) | UK gallons |
|---|---|---|
| 0.25 | 0.9464 | 0.2082 |
| 0.5 | 1.8927 | 0.4163 |
| 0.75 | 2.8391 | 0.6245 |
| 1 | 3.7854 | 0.8327 |
| 1.5 | 5.6781 | 1.249 |
| 2 | 7.5708 | 1.6653 |
| 2.5 | 9.4635 | 2.0817 |
| 3 | 11.3562 | 2.498 |
| 5 | 18.9271 | 4.1634 |
| 6 | 22.7125 | 4.996 |
| 7 | 26.4979 | 5.8287 |
| 10 | 37.8541 | 8.3267 |
| 14 | 52.9958 | 11.6574 |
| 15 | 56.7812 | 12.4901 |
| 20 | 75.7082 | 16.6535 |
| 26 | 98.4207 | 21.6495 |
| 30 | 113.5624 | 24.9802 |
| 40 | 151.4165 | 33.307 |
| 50 | 189.2706 | 41.6337 |
| 55 | 208.1976 | 45.7971 |
| 65 | 246.0518 | 54.1238 |
| 80 | 302.8329 | 66.6139 |
| 100 | 378.5412 | 83.2674 |
Liter to US Gallon chart
The reverse direction for values people often look up.
| Liter (L) | US Gallon (gal) |
|---|---|
| 0.5 | 0.1321 |
| 1 | 0.2642 |
| 3.5 | 0.9246 |
| 7.5 | 1.9813 |
| 11 | 2.9059 |
| 18.9 | 4.9929 |
| 23 | 6.076 |
| 35 | 9.246 |
| 57 | 15.0578 |
| 75 | 19.8129 |
| 113 | 29.8514 |
| 150 | 39.6258 |
| 189 | 49.9285 |
| 300 | 79.2516 |
Household capacities sold in US gallons
| Item | US Gallon (gal) | Liter (L) |
|---|---|---|
| Gallon jug of milk | 1 | 3.7854 |
| WaterSense toilet, maximum per flush | 1.28 | 4.8453 |
| US federal toilet limit per flush | 1.6 | 6.0567 |
| Office water-cooler bottle | 5 | 18.9271 |
| Classic starter aquarium | 10 | 37.8541 |
| Water heater tank, common 40-gallon size | 40 | 151.4165 |
| Water heater tank, common 50-gallon size | 50 | 189.2706 |
| Steel drum often reused as a rain barrel | 55 | 208.1976 |
Quick mental estimate
Multiply the gallons by 4, then take away 5% of the result: 10 gal → 40 − 2 = 38 L. That amounts to a factor of 3.8, about 0.4% above the exact 3.785411784.
Use the converter or the charts when the exact figure matters.
The two units
US Gallon (gal): The US liquid gallon is defined as exactly 231 cubic inches, which is 3.785411784 liters. It is the gallon used for gasoline, milk and water in the United States.
Liter (L): The liter is the metric unit of volume accepted for use with the SI. Since 1964 it has been defined as exactly one cubic decimeter, which is 1,000 cubic centimeters.
Frequently asked questions
How many liters are in 5 gallons?
5 US gallons is 18.93 L, so water-cooler bottles sold outside the US are often labeled 18.9 L. Five UK gallons would be a larger 22.73 L, which is why the country on a label matters.
Is a gallon of gasoline the same size as a gallon of milk?
Yes. Fuel, milk, paint and water in the US are all sold by the same liquid gallon of 231 cubic inches. A separate US dry gallon of about 4.405 L exists but is rarely used; produce such as berries is sold by the dry pint and dry quart instead.
How much does a gallon of water weigh in kilograms?
About 3.78 kg, or about 8.3 lb, at room temperature. A liter of water has a mass close to 1 kg, so for water the kilograms come out at roughly the same number as the liters; other liquids differ with their density.
How precise is the result?
The converter uses the exact definitions above with browser floating-point arithmetic and shows up to 12 significant digits. The charts round to four decimal places for reading.
Sources
Last updated:
Page address with these inputs: https://kakao.mobile/tools/us-gallon-to-liter-converter/
Cite or embed this tool
kakaoCalc. (2026, November 8). US Gallons to Liters Converter (gal to L). https://kakao.mobile/tools/us-gallon-to-liter-converter/
“US Gallons to Liters Converter (gal to L).” kakaoCalc, 8 Nov. 2026, kakao.mobile/tools/us-gallon-to-liter-converter/.
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