European fuel economy is quoted in liters per 100 kilometers, American cars in miles per gallon — and before you can compare them, the liters need to become gallons. The factor is 0.264172: multiply liters by it to get US gallons. Forty liters of fuel — a typical compact-car tank fill in Europe — is about 10.57 US gallons. A 5-liter oil jug is about 1.32 gallons. The spelling "litres" is the giveaway that the source is British or international, but the math is identical to "liters": the unit does not care how you spell it.

Type your value in the Litres box and the Gallons (US) readout multiplies by 0.264172. The 10-litre example gives 2.6417 gallons — the anchor worth memorizing, since 10 is the easiest scaling number. Reverse it with division: gallons × 3.78541 gives liters. The classic use case is fuel: a car rated at 6 liters per 100 km burns about 1.585 gallons per 62 miles, which works out to roughly 39 mpg — the conversion chain (liters to gallons, km to miles) that lets an American buyer judge a European spec sheet. Aquariums, water heaters, and paint cans cross the same bridge. Keep 0.264 in your head and any litre figure becomes gallons in one multiplication.

With the pre-filled defaults — Litres 10 — the Litres To Gallons Calculator returns Gallons (US) 2.6417. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.