Gallons to Liters Calculator
Enter volume in gallons
Result updates instantly
Current Conversion
1 US gal = 3.78541 L
Exact Formula
liters = gallons × conversion_factor
Common Volume Conversions
| Gallons | US to Liters | UK to Liters | Common Use |
|---|---|---|---|
| 1 gal | 3.785 L | 4.546 L | Milk jug |
| 2 gal | 7.571 L | 9.092 L | Small fuel can |
| 5 gal | 18.927 L | 22.730 L | Standard container |
| 10 gal | 37.854 L | 45.461 L | Medium fuel tank |
| 15 gal | 56.781 L | 68.191 L | Car fuel tank |
| 20 gal | 75.708 L | 90.922 L | Large container |
| 55 gal | 208.198 L | 250.035 L | Standard drum |
How This Gallons to Liters Calculator Works
Converting gallons to liters is a common need for international travel, fuel calculations, and understanding container capacities. This calculator provides instant, accurate conversions by multiplying the gallon amount by the appropriate conversion factor based on whether you’re using US gallons or UK imperial gallons.
Conversion Formula: The calculation follows this simple formula: Liters = Gallons × Conversion Factor. For US gallons: 1 gallon = 3.785411784 liters. For UK gallons: 1 gallon = 4.54609 liters. The calculator uses these exact conversion factors for precision.
Practical Example: If you have 10 US gallons of gasoline and want to convert to liters: 10 gal × 3.785411784 = 37.85411784 liters (approximately 37.85 L). For 10 UK gallons: 10 gal × 4.54609 = 45.4609 liters (approximately 45.46 L). This 7.6-liter difference shows why selecting the correct gallon type matters.
Important: Always verify which gallon type your measurement represents. US gallons are 20% smaller than UK gallons. Using the wrong type can lead to significant errors in fuel calculations, chemical mixing, or any application requiring precise volume measurements.
When You Need to Convert Gallons to Liters
International Fuel Planning
When traveling between the US/UK and metric-using countries, you need to convert fuel measurements. American drivers planning European trips need to understand how their car’s fuel tank capacity in gallons translates to liters at European gas stations. Similarly, UK drivers visiting Europe need this conversion for fuel planning and cost comparisons.
Container and Equipment Specifications
Industrial equipment, storage tanks, and containers often have capacity specifications in gallons or liters depending on their country of manufacture. Converting between these units helps you understand actual capacity, plan storage needs, and ensure compatibility with other equipment or regulations.
Fuel Efficiency Conversion: To convert miles per gallon (mpg) to liters per 100 km: Divide 235.215 by the mpg figure for US gallons, or divide 282.481 by the mpg figure for UK gallons. For example, 30 mpg (US) = 7.84 L/100km, while 30 mpg (UK) = 9.42 L/100km.
Chemical and Agricultural Applications
Farm chemicals, pool treatments, and industrial cleaning solutions often have mixing instructions based on gallons per acre or gallons per pool. When using metric measuring equipment or when regulations require metric reporting, converting gallons to liters ensures accurate mixing and compliance.
Cooking and Food Production
Large-scale cooking, brewing, and commercial food production often use gallon measurements for ingredients. Converting to liters helps when scaling recipes, using metric equipment, or complying with food labeling regulations in metric-using countries.
Understanding the Gallon Differences
United States Gallon
The US gallon, defined as exactly 231 cubic inches, equals 3.785411784 liters. It’s used for all liquid measurements in the United States, including gasoline, milk, paint, and chemicals. The US gallon is approximately 83.3% the size of a UK imperial gallon.
United Kingdom Imperial Gallon
The UK imperial gallon, defined as the volume of 10 pounds of water at 62°F, equals 4.54609 liters. It’s used in the United Kingdom for fuel, beer, and milk, though liters are increasingly common. The UK gallon is approximately 20% larger than the US gallon.
Canadian Context
Canada officially uses the metric system with liters as the standard volume unit. However, due to proximity and trade with the US, Canadians frequently encounter US gallons in practical contexts like fuel efficiency ratings, imported products, and cross-border shopping.
Australian Context
Australia uses the metric system exclusively for official measurements. Liters are standard for all volume measurements. Australians mainly need gallon conversions when dealing with American products, recipes, or historical references.
Common Conversion Mistakes to Avoid
Mistake 1: Assuming all gallons are equal – This is the most critical error. A 20-gallon fuel tank holds 75.7 liters if US gallons, but 90.9 liters if UK gallons. That’s a 15.2-liter difference that affects range calculations and fuel costs.
Mistake 2: Using 4 liters per gallon approximation – While “4 liters per gallon” is a useful mental approximation for US gallons, it’s not exact (3.785 L is exact). For UK gallons, the approximation would be 4.5 liters per gallon. For precise calculations, always use exact conversion factors.
Mistake 3: Forgetting temperature effects on volume – Volume measurements expand with heat and contract with cold. For scientific applications, specify standard conditions. For everyday use like fuel, the difference is minor but becomes significant for large volumes or precise scientific work.
Frequently Asked Questions
How many liters are in a gallon exactly?
There are exactly 3.785411784 liters in a US gallon and exactly 4.54609 liters in a UK imperial gallon. These are defined, exact conversions, not approximations.
Why do the US and UK have different gallons?
The systems developed independently from different historical standards. The US gallon is based on the 18th-century English wine gallon (231 cubic inches). The UK imperial gallon was redefined in 1824 based on the volume occupied by 10 pounds of water, creating a larger unit.
How can I tell if a measurement is US or UK gallons?
Check the context. American products, cars, and recipes use US gallons. British products and older UK measurements use imperial gallons. If unspecified and from the US, assume US gallons. If from the UK and pre-1970s, assume imperial gallons; if modern, it may be liters instead.
Are dry gallons different from liquid gallons?
Yes, the US has separate dry gallons for measuring dry commodities (4.404884 liters), but they are rarely used today. Liquid gallons are standard for fluids. The UK only has one imperial gallon for both liquid and dry measurements.
How do I convert fuel economy from mpg to L/100km?
Use these formulas: For US mpg to L/100km: 235.215 ÷ mpg. For UK mpg to L/100km: 282.481 ÷ mpg. For example, 30 US mpg = 7.84 L/100km, while 30 UK mpg = 9.42 L/100km.
Practical Examples for Everyday Use
Student Example: A physics student needs to convert 5 US gallons of water to liters for a density experiment. Using this calculator: 5 gal × 3.785411784 = 18.92705892 liters. They can measure exactly 18.93 liters for their experiment.
Traveler Example: An American renting a car in Europe needs to understand the 55-liter fuel tank capacity in terms they understand. 55 liters ÷ 3.785 = approximately 14.53 US gallons. They know this is similar to their car at home.
Homeowner Example: Someone in the UK buys a 50-liter water heater but is used to thinking in gallons. 50 liters ÷ 4.546 = approximately 11.0 UK gallons. They now understand the capacity in familiar terms.
Fuel Cost Example: A British traveler in the US sees gasoline priced at $3.50 per US gallon. To compare with UK prices (£1.40 per liter), they convert: $3.50 per US gallon ÷ 3.785 = $0.925 per liter. At current exchange rates, this helps them compare real costs.
Quick Estimation: For mental math, remember: US gallons × 3.8 ≈ liters, UK gallons × 4.5 ≈ liters. For反向conversion: liters ÷ 3.8 ≈ US gallons, liters ÷ 4.5 ≈ UK gallons. Use our calculator for exact figures.
Essential Volume Conversion Reference
| Measurement | US Gallons | Liters | UK Gallons |
|---|---|---|---|
| 1 quart | 0.25 gal | 0.946 L | 0.208 gal |
| 1 US gallon | 1 gal | 3.785 L | 0.833 gal |
| 1 UK gallon | 1.201 gal | 4.546 L | 1 gal |
| 5 US gallons | 5 gal | 18.927 L | 4.166 gal |
| 10 US gallons | 10 gal | 37.854 L | 8.327 gal |
| 20 US gallons | 20 gal | 75.708 L | 16.654 gal |
| 55 US gallons (drum) | 55 gal | 208.198 L | 45.799 gal |
| 100 US gallons | 100 gal | 378.541 L | 83.267 gal |
| 1 cubic foot | 7.481 gal | 28.317 L | 6.229 gal |
| 1 cubic meter | 264.172 gal | 1000 L | 219.969 gal |
Applications in Specific Fields
Automotive Industry
Car fuel tanks are typically measured in liters globally but often discussed in gallons in the US and UK. Understanding conversions helps when comparing vehicle specifications, calculating range, or understanding fuel efficiency ratings across different markets.
Agriculture and Farming
Pesticides, fertilizers, and irrigation often use gallons per acre measurements in the US. Converting to liters helps when using metric equipment, complying with international regulations, or following instructions from metric-using manufacturers.
Swimming Pool Maintenance
Pool chemical dosing instructions often assume gallons in the US and liters elsewhere. Converting accurately ensures proper chemical balance, preventing damage to pool surfaces or equipment from incorrect dosing.
Brewing and Beverage Industry
Commercial brewing often uses barrel measurements that convert to gallons or liters. Understanding these conversions helps with recipe scaling, equipment specification, and compliance with labeling regulations in different markets.
Accuracy Note: This calculator uses exact conversion factors for both US and UK gallons. For critical applications like chemical mixing or scientific work, always verify measurements with calibrated equipment and consider temperature effects on volume.