Liters ⇄ US Gallons Converter

How to convert liters to US gallons

To convert liters to US gallons, divide the value by 3.785411784, or multiply it by about 0.264172.

gal = L ÷ 3.785411784

Example: 10 L ÷ 3.785411784 = 2.64172 gal

How to convert US gallons to liters

To convert US gallons to liters, multiply the value by 3.785411784.

L = gal × 3.785411784

Example: 10 gal × 3.785411784 = 37.8541 L

1 L = 0.264172 gal · 1 gal = 3.78541 L

A US gallon is exactly 3.785411784 liters, or 128 US fluid ounces. The UK (imperial) gallon is about 20% larger at 4.54609 liters, so check which one is meant for fuel economy and recipes.

Liters and gallons

A liter is the volume of a cube 10 cm on each side. The US gallon is legally defined as 231 cubic inches and splits into 4 quarts, 8 pints or 16 cups, so a US quart (0.946 L) is just under a liter. In the United States, gasoline, milk and paint are sold by the gallon; nearly everywhere else, fuel and drinks are sold by the liter.

Fuel prices and tank sizes

When you compare fuel prices between countries, convert the price as well as the volume. Gas at $3.50 per US gallon costs about $0.92 per liter, and a price of 1.50 per liter is 5.68 per gallon. A car with a 50-liter tank holds 13.2 US gallons, while a 15-gallon tank holds about 56.8 liters.

Fuel economy: mpg, L/100 km and km/L

The US measures fuel economy in miles per gallon, where higher is better. Europe, China, Australia and Canada use liters per 100 km, where lower is better, and countries such as Korea and Japan use kilometers per liter. Because mpg and L/100 km are inverses of each other, there is no single factor between them: divide 235.2 by a US mpg figure to get L/100 km, and divide 235.2 by L/100 km to get US mpg.

British mpg figures use the larger imperial gallon, so the same car looks about 20% more economical: 30 UK mpg is only 25 US mpg. For UK mpg, use 282.5 instead of 235.2.

Quick mental math

• Liters to gallons: divide by 4, then add 5%. 40 L → 10 + 0.5 = 10.5 gal (exact: 10.57 gal), less than 1% low.
• Gallons to liters: multiply by 4, then subtract 5%. 15 gal → 60 − 3 = 57 L (exact: 56.78 L), within 0.4%.

Common mistakes

• Judging savings by mpg alone. Over 100 miles, going from 10 to 20 mpg saves 5 gallons, while going from 30 to 50 mpg saves only 1.3 gallons. L/100 km shows fuel use directly, so differences are easier to compare.
• Assuming a gallon always weighs the same. A US gallon of water weighs about 3.8 kg (8.3 lb), but a gallon of gasoline weighs only about 2.7–2.9 kg because gasoline is less dense than water.
• Picking up the dry gallon. The US also has a rarely used dry gallon of about 4.4 L for things like grain. Drinks and fuel always use the liquid gallon.

FAQ

How many liters is a 5-gallon water jug?

18.93 liters. Water-cooler bottles sold as “5 gallons” are often labeled 18.9 L.

How many gallons is a 2-liter bottle?

0.53 US gallons, a little over half a gallon.

How big is a 10-gallon aquarium in liters?

About 37.9 liters; a 20-gallon tank is about 75.7 liters. Remember that gravel and decorations take up part of that volume.

How many liters is a 50-gallon water heater?

About 189 liters. Smaller US tanks of 40 gallons hold about 151 liters.

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