How Many Liters in a Gallon

Convert gallons to liters instantly with support for both US and Imperial gallons. Includes conversion tables, formulas, and practical examples for cooking, fuel, and home projects.

Gallons to Liters Calculator

Ever tried following a British recipe only to end up with way too much liquid? Or puzzled over why your American car manual's fuel tank capacity doesn't match what you see at European gas stations? The culprit is usually a gallon conversion gone wrong.

This calculator handles the conversion both ways—gallons to liters and liters to gallons—with one crucial feature most converters skip: you can choose between US gallons and Imperial gallons. That distinction matters. An Imperial gallon is nearly 20% larger than a US gallon, so using the wrong one can seriously throw off your results.

Enter your number, pick your gallon type, and get your answer instantly.

Built by Selvo.

How to Use This Calculator

1. Pick your direction. Converting gallons to liters? Select that option. Going the other way? Choose "Liters to Gallons."

2. Type in your number. Decimals work fine—enter 2.5, 0.75, whatever you need.

3. Select US or Imperial gallon. Not sure which one? Keep reading—there's a whole section on this below.

4. Get your result. It updates the moment you enter your values. No buttons to click, no waiting.

How Many Liters in a Gallon?

Straight answer:

1 US gallon = 3.79 liters
1 Imperial gallon = 4.55 liters

If you're in the United States or using anything American—recipes, car specs, product labels—you need the US gallon number. That's 3.79 liters, or about four 1-liter bottles minus a small glass.

US Gallon vs Imperial Gallon: Why This Actually Matters

Here's where people get tripped up: there are two different gallons, and they're not even close to the same size.

The US gallon holds 3.785 liters. Every gas pump, milk jug, and paint can in America uses this measurement. It's been this way since the country was founded—the US simply kept the English wine gallon that colonists were already using.

The Imperial gallon holds 4.546 liters—about 20% more. Britain created this "new and improved" gallon in 1824, standardizing it as exactly 10 pounds of water. The thing is, the US had already been independent for nearly 50 years by then, so Americans never adopted the change.

This means a "gallon" in a 1960s British cookbook is genuinely a different amount than a "gallon" in an American one. Get this wrong and your recipe is off by a fifth.

Quick Guide: Which Gallon Do You Need?

Frequently Asked Questions

How many liters are in a US gallon?

3.785 liters, or 3.79 if you're rounding. Think of it as just under four 1-liter bottles.

How many liters are in an Imperial gallon?

4.546 liters—noticeably more than a US gallon. If you're used to US measurements, an Imperial gallon is roughly a US gallon plus an extra pint and a half.

What's the actual difference between US and Imperial gallons?

About 20%. The Imperial gallon holds 4.546 liters versus 3.785 for the US gallon. They come from different historical definitions: the US kept the old English wine gallon, while Britain redefined theirs in 1824 to equal exactly 10 pounds of water (which turned out to be larger).

How do I convert liters back to gallons?

Divide by 3.785 for US gallons, or by 4.546 for Imperial gallons. Or just flip the toggle on this calculator to "Liters to Gallons" and let it do the work.

How much is half a gallon in liters?

Half a US gallon is 1.89 liters—basically a standard large soda bottle. Half an Imperial gallon is 2.27 liters.

How many 2-liter bottles make a gallon?

About 1.9 bottles for a US gallon. So two 2-liter bottles give you just over a gallon (4 liters vs 3.79 liters).

Why did the US and UK end up with different gallons?

Timing. When the US declared independence in 1776, both countries used the same gallon—the wine gallon of 231 cubic inches. But in 1824, Britain passed the Imperial Weights and Measures Act, which created a new, larger gallon. By then, the US had been doing its own thing for almost 50 years and saw no reason to change.

Does Canada use US or Imperial gallons?

Officially, Canada uses metric—liters and milliliters. But it's complicated. Before metrication in the 1970s, Canada used Imperial gallons (the British ones). So older Canadian references mean Imperial, while anything modern is probably in liters.

How do I convert gallons to liters for a recipe?

Multiply US gallons by 3.785. So if a recipe calls for half a gallon of stock, that's 1.89 liters. For British recipes that mention gallons, use 4.546 instead—or you'll end up with 20% less liquid than intended.

Is a gallon a metric measurement?

No—it's an imperial/customary unit. The metric system uses liters for volume. The gallon persists mainly in the United States, and to some extent in the UK for things like fuel economy and draft beer. Most of the world went fully metric decades ago.