Convert Liters to Gallons (US)

How to convert liters to gallons

The working factor is 1 L = 0.264172 gal, and it never drifts, because the US liquid gallon is legally defined as exactly 231 cubic inches — that is 3.785411784 liters on the nose. Both units are fixed by definition, so the conversion between them is, too.

1. Take your volume in liters.
2. Multiply by 0.264172.
3. Round the result to whatever precision the situation needs.

Worked example: the 42 L fuel tank in a typical European hatchback holds 42 × 0.264172 = 11.0952 gal. Going the other direction, remember that 1 gal = 3.7854 L.

What is a liter?

The liter is the metric world’s everyday volume unit. The BIPM defines it as one cubic decimeter (1 L = 1 dm³) and accepts it for use alongside the SI, which is why it shows up on everything from fuel pumps in Europe to soft-drink bottles sold worldwide. If you grew up outside the United States, you almost certainly picture petrol, milk, and bottled water in liters before anything else.

What is a gallon (US)?

The US liquid gallon is a US customary unit fixed at 231 cubic inches, equal to 3.785411784 liters exactly. It remains the standard measure at American fuel stations and on milk jugs, water heaters, and buckets. Take care not to confuse it with the imperial gallon of older British usage — that one runs about 4.546 liters, so the same word names two different amounts depending on which side of the Atlantic printed the label.

When you’ll need liters to gallons

• Refueling a rental car in the US: if your car back home takes 50 L to fill from empty, that same fill is 13.2086 gal at an American pump — suddenly the posted per-gallon price means something.
• Making sense of miles per gallon: American fuel economy is quoted per gallon, so translating familiar quantities helps recalibrate your instincts; 40 L is 10.5669 gal, and 10 L is 2.6417 gal.
• Buying aquarium gear from US retailers: filters, heaters, and water treatments sold in America are rated in gallons. A 200 L tank works out to 52.8344 gal, which lets you match equipment ratings without guesswork.
• Dosing pool or spa chemicals: plenty of US-made chemical products state doses per gallon of water. A 1000 L spa holds 264.1721 gal — the figure the label actually asks for.
• Water-cooler bottles: the 20 L jug sitting on office coolers across much of the world converts to 5.2834 gal, which is why it looks nearly identical to the container Americans call the 5-gallon bottle.