Converting between gallons and liters is a common need for cooking, fuel calculations, and international travel. The US gallon and the imperial gallon are different measurements, so it's important to know which one you're working with.
The Conversion Formula
The conversion factors are fixed and based on the metric system definition of the liter. One US gallon equals approximately 3.78541 liters, while one imperial gallon (used in the UK and Commonwealth) equals approximately 4.54609 liters.
1 US gallon = 3.78541 liters
1 Imperial gallon = 4.54609 liters
To convert gallons to liters, multiply by the conversion factor:
Liters = Gallons Γ 3.78541 (US)
Liters = Gallons Γ 4.54609 (Imperial)
Worked Examples
Example 1: Convert 5 US gallons to liters
5 Γ 3.78541 = 18.93 liters
Example 2: Convert 10 Imperial gallons to liters
10 Γ 4.54609 = 45.46 liters
Example 3: Convert 2.5 US gallons (a common tank size)
2.5 Γ 3.78541 = 9.46 liters
Quick Reference Table
| Gallons (US) | Liters | Gallons (Imperial) | Liters |
|---|---|---|---|
| 1 | 3.785 | 1 | 4.546 |
| 2 | 7.571 | 2 | 9.092 |
| 5 | 18.93 | 5 | 22.73 |
| 10 | 37.85 | 10 | 45.46 |
| 20 | 75.71 | 20 | 90.92 |
| 50 | 189.3 | 50 | 227.3 |
Converting Liters Back to Gallons
To reverse the conversion and find how many gallons are in a given number of liters:
US Gallons = Liters Γ· 3.78541
Imperial Gallons = Liters Γ· 4.54609
Example: 15 liters to US gallons:
15 Γ· 3.78541 = 3.96 US gallons
Practical Uses
Gallons to liters conversions come up in many real-world scenarios:
- Fuel: US fuel economy is measured in miles per gallon (MPG), while most countries use liters per 100 km
- Cooking: US recipes use cups and gallons; metric recipes use milliliters and liters
- Water tanks: Aquarium and tank sizes are often listed in gallons in the US but liters elsewhere
- Beverages: Large drink containers in the US are measured in gallons at the grocery store
Common Conversions at a Glance
A US gallon of milk, a 5-gallon bucket commonly used for construction, or a standard water cooler jugβthese are all familiar items that help us understand volume. When traveling internationally or following recipes online, converting between these two systems becomes second nature.
Use our Volume Converter to convert between gallons, liters, cups, and all other volume units instantly.