Gallons to Liters Converter
Convert US gallons to liters instantly. Type any gallon value and get the exact liter result. Includes a common volumes table, formula, and fuel and storage examples.
Built and maintained by Will Henschell, Data Scientist. Editorial policy.
Liters (L)
Need the reverse? Convert liters to US gallons →
Common US gallons to Liters Conversions
| US gallons (gal) | liters (L) | Note |
|---|---|---|
| 0.5 gal | 1.893 L | ½ gal |
| 1 gal | 3.785 L | 1 gal |
| 2 gal | 7.571 L | 2 gal |
| 5 gal | 18.927 L | 5 gal |
| 10 gal | 37.854 L | 10 gal |
| 15 gal | 56.781 L | 15 gal |
| 20 gal | 75.708 L | 20 gal |
| 55 gal | 208.197 L | 55 gal drum |
The Gallons-to-Liters Formula
1 US liquid gallon = 231 cubic inches exactly. Since 1 inch = 0.0254 m, 1 cubic inch = (0.0254)³ m³ = 0.016387064 liters. Therefore 1 US gallon = 231 × 0.016387064 = 3.785411784 liters exactly. To convert US gallons to liters, multiply by 3.78541. For a quick estimate, multiply by 3.8 — accurate within 0.4%. Note: the UK (imperial) gallon = 4.54609 liters — about 20% larger than the US gallon. This converter uses the US liquid gallon.
Gallons and Liters for Fuel
Fuel is sold by the liter in most countries and by the gallon in the US. This creates a perceived price difference: gas at $3.50/US gallon = $0.92/liter; European petrol at €1.60/liter ≈ €6.06/gallon. US car fuel economy is expressed in miles per gallon (mpg); most of the world uses liters per 100 km (L/100km). To convert: L/100km = 235.214 ÷ mpg. A 30 mpg car uses about 7.84 L/100km. A 40 mpg car uses about 5.88 L/100km.
Gallons in Water, Pools, and Storage Tanks
Water containers and tanks in the US are sized in gallons. A standard water heater holds 40–80 gallons (151–303 liters). A residential swimming pool holds 15,000–25,000 gallons (56,781–94,635 liters). Standard aquarium sizes: a '55-gallon tank' = 208 liters; a '10-gallon tank' = 37.9 liters. Daily water intake: the common recommendation of 8 cups (64 fl oz) = ½ US gallon = 1.89 liters. A standard 5-gallon water cooler jug = 18.93 liters.
Frequently Asked Questions
How many liters is 1 US gallon?
1 US liquid gallon equals exactly 3.785411784 liters, commonly rounded to 3.785 L. The UK imperial gallon is 4.546 L — about 20% larger.
How do I convert gallons to liters?
Multiply US gallons by 3.785. For a quick estimate, multiply by 3.8. Example: 5 gallons × 3.785 = 18.93 liters.
What is the difference between a US gallon and a UK gallon?
A US liquid gallon = 3.785 liters. A UK (imperial) gallon = 4.546 liters — about 20% larger. This matters for fuel economy comparisons: 40 mpg (US) ≈ 48 mpg (UK) and ≈ 5.9 L/100km.
How many liters is a 55-gallon drum?
55 US gallons × 3.78541 = 208.2 liters. A standard 55-gallon industrial drum holds approximately 208 liters of liquid.