Gallons to Liters Converter
Result
3.78541 liters
Also Equal To
How Gallons to Liters Conversion Works
A gallon-to-liter conversion translates a volume measurement from the gallon unit (US or Imperial) into the metric liter, the standard volume unit used worldwide. One US liquid gallon equals exactly 3.785411784 liters, as defined by the National Institute of Standards and Technology (NIST). One Imperial gallon equals approximately 4.54609 liters.
This conversion is essential for fuel calculations, cooking large batches, homebrewing, aquarium management, and international trade. According to the US Energy Information Administration (EIA), Americans consume approximately 369 million gallons of gasoline per day (1.4 billion liters). The rest of the world measures fuel in liters -- understanding this conversion is critical for comparing fuel prices and vehicle efficiency across countries.
Our Liters to Gallons Converter handles the reverse calculation. For cooking volume conversions, see the Cooking Converter, and for all volume units, use the Volume Converter.
The Gallons to Liters Formula
The formula multiplies the gallon value by its liter equivalent:
Liters = Gallons x Conversion Factor
- US gallon: multiply by 3.78541
- Imperial gallon: multiply by 4.54609
Worked example: Your car's fuel tank holds 15 US gallons. In liters: 15 x 3.78541 = 56.78 liters. When traveling in Europe where pump prices are per liter, this tells you that filling from empty costs about 56.8 liters. At a European fuel price of EUR 1.70/liter, a full tank costs about EUR 96.50.
Key Terms You Should Know
- US Liquid Gallon -- Equal to 3.78541 liters, 128 US fluid ounces, or 4 US quarts. Derived from the English wine gallon and standardized by the US government. Used for fuel, milk, water, and other liquid sales in the US.
- Imperial Gallon -- Equal to 4.54609 liters or 160 Imperial fluid ounces. Defined in 1824 as the volume of 10 pounds of water at 62 degrees F. Used historically in the UK, Canada, and Commonwealth countries, though most have now switched to liters.
- Liter (L) -- A metric unit of volume equal to 1,000 milliliters or 1 cubic decimeter. The liter is the global standard for liquid volume measurement in commerce, science, and everyday life outside the US.
- US Dry Gallon -- Equal to 4.405 liters, used historically for dry goods like grain. Rarely encountered today. Do not confuse with the US liquid gallon (3.785 L).
- Quart -- One quarter of a gallon. A US quart equals 0.9464 liters, and an Imperial quart equals 1.1365 liters. US milk is often sold in quart containers.
Gallons to Liters Conversion Table
Common gallon-to-liter conversions for both US and Imperial gallons, based on NIST-defined factors.
| Gallons | US Gallons (L) | Imperial Gallons (L) |
|---|---|---|
| 0.5 | 1.893 | 2.273 |
| 1 | 3.785 | 4.546 |
| 2 | 7.571 | 9.092 |
| 3 | 11.356 | 13.638 |
| 5 | 18.927 | 22.730 |
| 10 | 37.854 | 45.461 |
| 15 | 56.781 | 68.191 |
| 20 | 75.708 | 90.922 |
| 50 | 189.271 | 227.305 |
| 100 | 378.541 | 454.609 |
Practical Examples
Comparing fuel prices internationally: US gasoline costs $3.50 per gallon. European fuel costs EUR 1.70 per liter. To compare: $3.50 / 3.78541 = $0.924 per liter. At an exchange rate of $1.08/EUR, the European price is $1.836 per liter. European fuel is about twice as expensive per liter as US fuel -- largely due to higher fuel taxes. Use our Fuel Efficiency Converter for mpg-to-L/100km conversions.
Aquarium water volume: Your 55-gallon fish tank needs a water treatment dosed at 5 mL per 10 liters. Converting: 55 x 3.78541 = 208.2 liters. Treatment needed: 208.2 / 10 x 5 = 104.1 mL. If you used gallons without converting, you would underdose by about 73%. Use our Aquarium Calculator for tank volume calculations.
Homebrewing recipe scaling: A 5-gallon homebrew recipe needs to be scaled for a 20-liter European fermenter. 5 US gallons = 18.93 liters. The 20-liter fermenter is about 5.6% larger, so you would scale all ingredients up by 1.056x. This small difference can affect bitterness and flavor balance in beer, so precise conversion matters.
Tips for Accurate Gallons to Liters Conversion
- Use the "multiply by 3.8" shortcut: For US gallons, 3.8 is within 0.4% of the exact factor. Example: 10 gallons x 3.8 = 38 liters (exact: 37.85). Close enough for most purposes.
- Always verify US vs Imperial: The 20% difference between US and Imperial gallons is significant. If you see "mpg" on a US car, it uses US gallons. UK fuel economy figures use Imperial gallons, giving a higher mpg number for the same vehicle.
- Remember the "4 liters per gallon" approximation: 1 US gallon is roughly 4 liters (overestimates by 5.7%). This is the simplest mental shortcut and works well for quick estimates.
- For fuel economy, use the L/100km formula: Divide 235.215 by US mpg to get L/100km. A car getting 25 mpg uses 235.215 / 25 = 9.41 L/100km. For Imperial mpg, divide 282.481 instead.
- Check container labeling: US milk jugs are labeled in gallons, but many US beverage containers (soda, water) already show metric equivalents. A "2-liter" soda bottle is 0.528 US gallons.
The History of the Gallon
The gallon has a complex history that explains why US and Imperial gallons differ. The US gallon descends from the English wine gallon (defined by Queen Anne in 1706 as 231 cubic inches), which the American colonies adopted before independence. In 1824, the British Parliament redefined the Imperial gallon as the volume of 10 pounds of distilled water at 62 degrees Fahrenheit, resulting in a larger gallon of about 277.42 cubic inches. The US kept the older, smaller wine gallon. Today, Canada has officially adopted the liter for fuel sales, the UK sells fuel in liters (though fuel economy is still quoted in mpg using Imperial gallons), and the US remains the only major country that sells fuel by the gallon.
Frequently Asked Questions
How many liters are in 1 gallon?
One US liquid gallon equals exactly 3.785411784 liters, as defined by NIST. One Imperial gallon equals approximately 4.54609 liters. The Imperial gallon is about 20% larger than the US gallon. This difference dates back to 1824 when the British redefined the gallon. Always verify which gallon type is being referenced in your conversion.
What is the difference between a US gallon and an Imperial gallon?
A US gallon equals 3.785 liters while an Imperial gallon equals 4.546 liters -- the Imperial gallon is 20.1% larger. The US gallon contains 128 US fluid ounces (4 quarts of 32 oz each), while the Imperial gallon contains 160 Imperial fluid ounces (4 quarts of 40 oz each). When a US car's fuel economy is rated at 30 mpg, the equivalent in Imperial gallons would be about 36 mpg. This distinction is critical for fuel calculations and recipe conversions.
How many liters is 5 gallons?
5 US gallons equals approximately 18.927 liters. The calculation is 5 x 3.78541 = 18.927 liters. This is a frequently searched conversion because 5-gallon containers are standard in the US for water cooler bottles, paint buckets, and homebrew fermenters. For Imperial gallons, 5 gallons equals 22.73 liters. A 5-gallon US water cooler jug holds about 19 liters, weighing approximately 18.9 kg (41.7 pounds) when full.
How do I convert gallons to liters for fuel economy?
To convert miles per gallon (mpg) to liters per 100 kilometers (L/100km), divide 235.215 by the US mpg value. For example, 30 mpg equals 235.215 / 30 = 7.84 L/100km. For Imperial mpg, divide 282.481 by the mpg value. The EPA reports that the average new US vehicle achieves about 26 mpg (9.05 L/100km). European fuel economy uses L/100km where lower numbers mean better efficiency. Use our Fuel Efficiency Converter for direct conversions.
Is a gallon of water the same as a gallon of milk?
Yes, by volume -- both are exactly 1 US gallon (3.785 liters). However, they differ by weight because milk is denser than water. A US gallon of water weighs 8.345 pounds (3.785 kg), while a US gallon of whole milk weighs approximately 8.6 pounds (3.9 kg) due to dissolved fats, proteins, and sugars. The USDA reports that whole milk has a density of about 1.03 g/mL compared to water's 1.0 g/mL. Volume measurements like gallons and liters measure space, not weight.
How many gallons is a liter?
One liter equals approximately 0.2642 US gallons or 0.2200 Imperial gallons. To convert liters to US gallons, divide by 3.78541 (or multiply by 0.264172). For example, a 2-liter bottle of soda equals 2 x 0.264172 = 0.528 US gallons, which is just over half a gallon. A 1-liter bottle equals about 1.06 US quarts. Use our Liters to Gallons Converter for precise reverse conversions.