How to Convert Gallons to Liters

Gallons are used for volume in several countries, but their size depends on the measurement system. The US liquid gallon and imperial gallon are not the same.

US Gallons to Liters Formula

Multiply US gallons by 3.785411784.

Liters = US Gallons × 3.785411784

Common Examples

• 1 US gallon ≈ 3.78541 liters
• 2 US gallons ≈ 7.57082 liters
• 5 US gallons ≈ 18.9271 liters
• 10 US gallons ≈ 37.8541 liters

US and Imperial Gallons

An imperial gallon is larger than a US liquid gallon. One imperial gallon is approximately 4.54609 liters. If a source does not clearly identify the gallon type, check its region or measurement standard before calculating.

Example

For 5 US gallons, multiply 5 by 3.785411784 to get approximately 18.9271 liters.

Online Conversion

A gallons-to-liters converter makes it easy to switch between volume systems when reading international specifications or planning quantities.

US Gallons and Imperial Gallons Are Different

When converting gallons to liters, the most important step is identifying the gallon standard. A US liquid gallon and an imperial gallon are different volumes, so using the wrong factor can produce a meaningful error.

For US gallons, multiply by 3.785411784. For imperial gallons, multiply by approximately 4.54609. If the source is from the United States, a US liquid gallon is generally the relevant standard unless it says otherwise.

Quick Conversion Reference

US Gallons	Liters
1	3.78541
2	7.57082
5	18.92706
10	37.85412
20	75.70824

Frequently Asked Questions

How many liters are in 5 US gallons?

5 US gallons are approximately 18.9271 liters.

How many liters are in an imperial gallon?

One imperial gallon is approximately 4.54609 liters.

Why do online results differ?

The most common reason is that different gallon standards are being used.

Related Conversion Guides

• Liters to Gallons: Formula, Examples, and Quick Guide
• Cups to ML: Formula, Examples, and Cooking Guide

Check the Source Region

If you find a gallon measurement online, look at the source before converting it. A US product page, an American recipe, and a US vehicle specification will normally use the US liquid gallon when gallons are involved. British or other imperial-system material may use imperial gallons instead. When the standard is unclear, state which conversion you used in your notes. That makes the result easier for another person to verify.