Gallons to Liters Converter
Convert between gallons (US/Imperial), liters, quarts, and fluid ounces. Enter values for instant results with step-by-step formulas.
Formula
L = US gal x 3.78541 | US gal = L / 3.78541 | 1 gal = 4 qt = 8 pt = 16 cups = 128 fl oz
All volume conversions use milliliters as the base unit. One US gallon equals exactly 231 cubic inches or 3,785.41 mL. One UK (imperial) gallon equals 4,546.09 mL. The metric system uses liters (1 L = 1,000 mL = 1 cubic decimeter). US liquid measurements follow the hierarchy: gallon > quart > pint > cup > fluid ounce.
Worked Examples
Example 1: Fuel Tank Conversion
Problem: A car has a 15 US gallon fuel tank. How many liters does it hold?
Solution: Liters = US gallons x 3.78541\nLiters = 15 x 3.78541 = 56.78 L\nAlso: 15 US gal = 12.49 UK gal\n= 60 quarts = 120 pints = 240 cups
Result: 15 US gal = 56.78 L = 12.49 UK gal
Example 2: Recipe Scaling
Problem: A recipe needs 500 mL of milk. How many cups is that?
Solution: Cups = mL / 236.588\nCups = 500 / 236.588 = 2.113 cups\nApproximately 2 cups and 2 tablespoons\nAlso: 500 mL = 0.5 L = 16.91 fl oz
Result: 500 mL = 2.11 cups = 16.91 fl oz = 0.132 US gal
Frequently Asked Questions
How do I convert gallons to liters?
To convert US gallons to liters, multiply by 3.78541. For example, 5 US gallons = 5 x 3.78541 = 18.927 liters. For UK (imperial) gallons, multiply by 4.54609. So 5 UK gallons = 5 x 4.54609 = 22.73 liters. A quick estimate for US gallons: multiply by 3.8 (or roughly 4 minus 5%). For UK gallons, multiply by 4.5. The US gallon is about 83% the size of the UK gallon.
What is the difference between US and UK gallons?
A US gallon equals 3.78541 liters (128 US fluid ounces), while a UK (imperial) gallon equals 4.54609 liters (160 imperial fluid ounces). The UK gallon is about 20% larger. This difference dates back to 1824 when Britain redefined the gallon as the volume of 10 pounds of water. The US retained the older Queen Anne wine gallon (231 cubic inches). This means fuel economy figures differ — 30 mpg (US) equals about 36 mpg (UK) and 7.84 L/100km.
How many liters are in a standard water bottle?
Standard single-serve water bottles typically hold 500 mL, which is 0.5 liters or about 16.9 US fluid ounces. Larger reusable bottles commonly come in 750 mL and 1-liter sizes. A 1-gallon water jug holds 3.785 liters. Five-gallon water cooler jugs hold 18.93 liters. Knowing these conversions helps when tracking daily water intake, as health guidelines often recommend 2 to 3 liters of water per day for adults.
How many gallons of gas does a typical car tank hold?
Most passenger cars have fuel tanks ranging from 12 to 16 US gallons, which equals 45 to 61 liters. Compact cars typically hold 10 to 13 gallons (38 to 49 liters), sedans hold 13 to 16 gallons (49 to 61 liters), and SUVs or trucks hold 18 to 36 gallons (68 to 136 liters). Knowing the conversion helps when traveling internationally, as fuel is sold in liters in most countries outside the United States. At current fuel prices, the difference between gallons and liters is important for accurate cost comparisons.
Can I use Gallons to Liters Converter on a mobile device?
Yes. All calculators on NovaCalculator are fully responsive and work on smartphones, tablets, and desktops. The layout adapts automatically to your screen size.
Can I use the results for professional or academic purposes?
You may use the results for reference and educational purposes. For professional reports, academic papers, or critical decisions, we recommend verifying outputs against peer-reviewed sources or consulting a qualified expert in the relevant field.