Gallons to Liters
Convert Gallons to Liters instantly.
How to Convert Gallons to Liters
To convert US gallons to liters, multiply by 3.78541. One US liquid gallon equals exactly 3.78541 liters. The gallon is widely used in the United States for fuel, water, milk, and other liquids, while most of the world uses liters. This conversion is important for travelers renting cars abroad (fuel is sold in liters globally except in the US), for comparing fuel efficiency (mpg vs. L/100km), and for understanding large volume measurements like water tank capacity or pool volume.
Gallons to Liters Reference Chart
Common conversions: 1 gal = 3.785 L · 2 gal = 7.571 L · 5 gal = 18.927 L · 10 gal = 37.854 L · 20 gal = 75.708 L · 50 gal = 189.271 L · 100 gal = 378.541 L.
Frequently Asked Questions
How many liters are in a gallon?
One US liquid gallon equals exactly 3.78541 liters. Note that the UK (imperial) gallon is larger at 4.54609 liters. When buying fuel in Canada or the UK, be aware that their gallons differ from US gallons — fuel prices per liter or per imperial gallon will look different from US per-gallon prices.
How many gallons is 20 liters?
20 liters ÷ 3.78541 = 5.28 US gallons. This is a useful conversion for understanding fuel tank sizes — a 20-liter fuel can holds about 5.3 gallons, and a 50-liter car fuel tank holds about 13.2 gallons.
How do I convert miles per gallon to liters per 100km?
To convert mpg to L/100km, divide 235.21 by the mpg value. For example, 30 mpg = 235.21 ÷ 30 = 7.84 L/100km. To go the other way, divide 235.21 by L/100km to get mpg. A car getting 8 L/100km = 235.21 ÷ 8 = 29.4 mpg.
Why does the US use gallons while most countries use liters?
The US retained the gallon from the British imperial system after independence and never converted to the metric system for everyday liquid measurement. The US gallon was historically defined differently from the British imperial gallon — they diverged in the 1820s when Britain redefined its gallon. Today, the US gallon (3.785 L) is used in the US, while the imperial gallon (4.546 L) is used in some Commonwealth countries, and liters are used everywhere else.