Once upon a time, the gallon (gal) was a popular measurement unit primarily used to measure the volume of beer and wine. But, by the end of the 18th century, there were three definitions of a gallon, each with a different volume.

Since the days of old, we have seen a shift towards measuring the volume of liquids in liters since it’s a uniform measurement unit that doesn’t change.

However, some countries still use gallons for various uses, which means it’s essential to know how to convert between the two. That’s what we’ll explore in this article.

We’ll also explain the three different definitions of gallons, how many liters are in each, how gallons are used globally, and more.

To answer this question, you must first know which gallon measurement you are converting to. There are three different gallon unit measurements, each with different volumes – the imperial gallon, the US liquid gallon, and the US dry gallon.

There are 4.546 liters in an imperial gallon, 3.785 liters in a US liquid gallon, and 4.405 liters in a US dry gallon. Before we further explore these different gallon measurements, let’s briefly explain what a liter and gallon are.

A liter is a unit of measurement used to determine volume. As part of the metric system, it is the primary measurement unit used to measure liquid capacity worldwide. It’s not an official measurement unit of the International System of Units (SI). However, it is still accepted for use with SI and is prevalent in scientific research. This also explains why you can use SI prefixes with liters – e.g., milliliters, centiliters, deciliters.

Initially, one liter was exactly the volume of 1 kilogram of liquid. This was because the kilogram scale was originally defined as the mass of one cubic decimetre (1000 cm³). However, subsequent changes to the definition of a meter and kilogram have meant that one liter does not equate precisely to the volume of 1 kilogram of liquid.

A liter is typically used to measure the volume of liquids and small solids, such as rice and grains, as they can mold their shape to the container they are placed in.

Much like liters, a gallon is a measurement unit used to measure liquid capacity. It is not as widely used as liters, but it still has uses in the United States of America, the United Kingdom, Canada, Central and South America, and some Caribbean nations.

When it comes to gallons, a key distinction has to be made about whether you are using the imperial gallon, US liquid gallon, or the US dry gallon. All three have different accepted volumes and are used in different areas of the world, which can confuse matters.

You may notice that when it comes to gallons, the temperature of the liquid is stated. This is because the volume or mass of a liquid can vary depending on its temperature.

Imperial gallons, also known as the UK gallon or British gallon, are predominantly used in the United Kingdom and its previous colonies such as Canada, Antigua, St. Lucia, Bahamas, Cayman Islands, and other Caribbean nations.

When rounded up, the imperial gallon equates to 4.546 liters (4.54609 to be exact) or 277.42 cubic inches. This means that one imperial gallon equates to 4.546 kilograms, or 10 pounds (lbs), of water at a temperature of 17 °C. The imperial gallon can be divided into four quarts, with each quart consisting of two pints. Each pint then equates to 20 imperial fluid ounces.

The US liquid gallon, also known as the US fluid gallon, is predominantly used in the United States of America, Dominican Republic, Colombia, Belize, Ecuador, Haiti, and a few other Central American countries.

A US gallon equates to 3.785 liters or 231 cubic inches. This means that one US gallon equates to 3.78 kg, or 8.34 pounds (lbs), of water at a temperature of 17 °C, making it 16.6% lighter than its imperial counterpart. Much like the imperial gallon, US liquid gallons can be divided into four quarts, with each quart consisting of two pints. However, the difference is that each pint equates to 16 US fluid ounces.

Lastly, we have the US dry gallon, which can be used to measure dried goods. One US dry gallon equates to 4.405 liters or 268.8025 cubic inches. Although it is a unit of measurement for dry products, it is rarely used in the real world.

Gallons were originally used in the United Kingdom to measure beer and wine. In more recent history, the gallon measurement unit has been used to buy and sell gasoline, something that is becoming increasingly uncommon.

The UK, European Union (EU), and many other countries worldwide have switched from gallons to liters when measuring and trading gasoline. However, in the United States of America, Colombia, Dominican Republic, Belize, Ecuador, Haiti, Guatemala, Honduras, Nicaragua, Peru, and other Central and South American countries, the US liquid gallon is still used to buy and sell gasoline.

You can convert gallons to liters and vice versa with our unit conversion calculator or use a conversion formula if you want to work it out yourself. You just need to be mindful of which gallon measurement you are converting to or from – Imperial or US liquid. The formula is as follows:

(Volume in gal) x (liters/1 gal) = Volume in liters

For instance, suppose we wanted to convert five imperial gallons into liters, we would substitute the relevant values into the formula to reach our final answer. It’s important to remember that since we are converting imperial gallons into liters, we need to put 4.546 liters into the second part of the equation. Let’s see how this would look

• (5 imperial gallons) x (4.546 liters) = 22.73 liters

Suppose we wanted to convert 5 US liquid gallons into liters. We can follow the same formula, except we would need to put 3.785 liters in the second part of the equation.

• (5 US liquid gallons) x (3.785 liters) = 18.925 liters

One liter equates to 0.26416 US liquid gallons. Knowing this, you have to make a simple calculation to convert liters to US liquid gallons:

(Volume in liters) x (0.26417 gal) = Volume in US liquid gallons)

One liter equates to 0.21997 imperial gallons. Knowing this, you have to make a simple calculation to convert liters to imperial gallons:

(Volume in liters) x (0.21997 gal) = Volume in imperial gallons)