Need to convert gallons to liters? Whether you're comparing fuel prices between countries, following a large-scale recipe, calculating water consumption, or figuring out how much paint you need for a room, converting gallons to liters is a critical volume conversion. This guide provides the exact formula, comprehensive conversion tables covering US and UK gallons, a free calculator, and practical examples for cooking, fuel economy, and everyday use.
The gallon is a unit of volume in the imperial and United States customary systems, primarily used in the United States for fuel, beverages, and liquid storage. The liter (or litre) is a metric unit of volume used worldwide. The conversion depends on which type of gallon you're using: 1 US gallon equals approximately 3.785 liters, while 1 UK (imperial) gallon equals approximately 4.546 liters. This is a significant difference — about 20% — so it's crucial to know which gallon system you're working with.
Gallons to liters conversion is essential in many real-world scenarios. When you rent a car in Europe and the fuel tank capacity is listed in liters but you're used to thinking in gallons, you need this conversion. When you compare water bills (charged per gallon in the US, per cubic meter in Europe), you need to convert. When you brew beer, make wine, or cook in large batches, recipes may use either system. Even aquarium hobbyists need to convert between gallons and liters to calculate water volume and treatment dosages.
This guide covers both US and UK gallons, provides detailed conversion tables, and includes practical examples for the most common use cases.
US Gallons to Liters:
liters = US gallons × 3.78541
UK (Imperial) Gallons to Liters:
liters = UK gallons × 4.54609
Quick approximation (US): liters = US gallons × 3.8 (within 0.4% for most values)
liters = US gallons × 3.8
Quick approximation (UK): liters = UK gallons × 4.5 (within 1% for most values)
liters = UK gallons × 4.5
The US gallon is legally defined as exactly 231 cubic inches, which equals approximately 3.785411784 liters. It is divided into 128 US fluid ounces or 4 US quarts. The UK (imperial) gallon is defined as exactly 4.54609 liters and is divided into 160 imperial fluid ounces or 4 imperial quarts. The imperial gallon is about 20% larger than the US gallon.
The difference originates from historical definitions. The US gallon was based on the English wine gallon (used for wine and other liquids), while the imperial gallon was redefined in 1824 based on the volume of 10 pounds of distilled water at a specific temperature. This divergence means that if you're reading a British recipe from before the 1970s or looking at fuel economy figures from the UK, you may be dealing with imperial gallons rather than US gallons.
Enter volume in US gallons
The following table uses US gallons (the standard in the United States and most online references). If you need UK gallons, multiply the US gallon value by 1.20095 or use the UK formula above.
When comparing fuel efficiency internationally, the US uses miles per gallon (MPG) while most of the world uses liters per 100 kilometers (L/100km). Here's a conversion reference for the most common fuel economy figures.
Example 1: Converting fuel tank capacity
A car's fuel tank holds 15 US gallons. What's the capacity in liters?
liters = 15 × 3.78541 = 56.78 liters
If you're renting a car in Europe and see the tank holds "55 liters," you now know that's approximately 14.5 US gallons — slightly less than a standard American car's 15-gallon tank.
Example 2: Converting water consumption
Your US water bill says you used 3,000 gallons this month. How many liters is that?
liters = 3,000 × 3.78541 = 11,356.23 liters
That's about 11.36 cubic meters (since 1 m³ = 1,000 liters). In Europe, water is typically billed per cubic meter, so this conversion helps you compare costs.
Example 3: Converting a recipe
A large batch recipe calls for 2.5 gallons of stock. How many liters do you need?
liters = 2.5 × 3.78541 = 9.46 liters
Since most metric measuring containers come in 1-liter or 5-liter sizes, you'd need approximately 9.5 liters — just under two 5-liter containers.
Example 4: Converting paint coverage
A paint can says it covers 400 sq ft per gallon. You need to paint 30 sq m. How many liters of paint do you need?
First, convert the coverage: 400 sq ft = 37.16 sq m per gallon (400 × 0.0929).
Liters needed: 30 ÷ 37.16 × 3.78541 = 3.06 liters
Round up and buy a 4-liter can (about 1 US gallon) to ensure you have enough with some leftover for touch-ups.
The most common use of gallons to liters conversion is for fuel. In the US, gasoline is sold by the gallon, and fuel economy is measured in miles per gallon (MPG). In Europe, Asia, and most of the world, fuel is sold by the liter, and economy is measured in liters per 100 kilometers (L/100km). Converting between these systems is essential when comparing car efficiency, calculating fuel costs for road trips, or shopping for vehicles from international manufacturers. Note: UK MPG uses imperial gallons, not US gallons — a UK MPG figure will be about 20% higher than the equivalent US MPG figure.
Large-scale cooking, commercial kitchens, home brewing, and winemaking often require converting between gallons and liters. A typical homebrew beer batch is 5 gallons (18.9 liters). A standard wine kit makes 6 gallons (22.7 liters). Commercial soup recipes, sauce production, and canning operations frequently use gallon measurements that need conversion for international operations.
Water consumption, storage, and treatment are measured differently around the world. US water bills charge per 1,000 gallons, while European bills charge per cubic meter (1 m³ = 1,000 liters = 264.17 US gallons). Aquariums are sized in gallons in the US but liters elsewhere. Swimming pools are measured in gallons in America but cubic meters or liters internationally. Rainwater harvesting systems, irrigation planning, and plumbing calculations all benefit from understanding both units.
Agricultural chemicals, fertilizers, and pesticides are often applied at rates specified per gallon per acre (US) or per liter per hectare (metric). Converting between these units is essential for international agricultural operations. Industrial processes, chemical manufacturing, and petroleum refining also frequently require volume conversions between gallons and liters.
Understanding the difference between US and UK gallons prevents costly mistakes:
In practice: if a UK car gets "50 MPG," that's equivalent to about "41.6 US MPG." If a British recipe calls for "1 gallon of water," that's about 4.55 liters, not 3.79 liters. Always check the context when you encounter "gallon" in international content.
1 US gallon equals 3.78541 liters. 1 UK (imperial) gallon equals 4.54609 liters. The US gallon is the standard in the United States and most Latin American countries, while the UK gallon is still used in some Commonwealth countries for specific applications (like fuel economy in the UK).
A standard US 5-gallon bucket holds 18.93 liters. These buckets (available at any hardware store) are one of the most common household containers in America. If you're using one for a metric recipe or measurement, this conversion is essential.
1 liter equals approximately 0.264 US gallons (or about 1/4 gallon). More precisely, 1 liter = 0.264172 US gallons. For quick estimation, 4 liters is just slightly more than 1 US gallon (4 × 0.264 = 1.056 gallons).
The formula is: L/100km = 235.215 ÷ MPG. For example, 30 MPG = 235.215 ÷ 30 = 7.84 L/100km. For UK MPG to L/100km, use: L/100km = 282.481 ÷ UK MPG. These conversions are essential when comparing fuel economy figures from different countries.
L/100km = 235.215 ÷ MPG
L/100km = 282.481 ÷ UK MPG
No. A US gallon (3.785 liters) is about 83.3% of an imperial gallon (4.546 liters). The imperial gallon is approximately 20% larger. This difference matters significantly for fuel economy comparisons — a car getting 40 UK MPG gets about 33 US MPG. Always verify which gallon system is being referenced.
The average American uses about 80-100 gallons (303-378 liters) of water per day, including indoor use (drinking, cooking, bathing, laundry, toilet) and outdoor use (watering, car washing). The European average is much lower, around 150 liters (40 gallons) per day, due to smaller homes, front-loading washing machines, and lower outdoor water use.
Need other volume conversions? Try these free tools from RiseTop:
Instant gallon to liter conversion
Reverse: liters to gallons
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Convert fuel economy units
Convert between all volume units
Last updated: April 2026. Default conversions use the US gallon (1 gal = 3.78541 liters). Use our gallons to liters converter for instant calculations with US/UK toggle.