What Is a Gallon?

Gallon: supporting image

A gallon is a customary unit of volume and capacity for liquid measure. 

It is commonly used in the Imperial systems and US customary standards of measurement.

The abbreviation for gallon is gal. 

Definitions and Divisions

In the US, there are different divisions of gallons.

US Gallon

US Liquid Gallon

It is a unit of measurement for liquids.

1 US liquid gallon $= 3.785412$ liters

                               $= 231$ cubic inches

US Dry Gallon

It is a unit of measurement for dry materials.

1 US dry gallon $= 4.404884$ liters

                           $= 268.8025$ cubic inches

Gallon: supporting image

Alt tag: Gallon, half-gallon, quart, pint, cup

  • Both US liquid and US dry gallons can be further divided.

1 gallon $= 4$ quarts

                $= 8$ pints

                 $= 16$ cups

                $= 32$ gills 

               $= 128$ fluid ounces

One gallon comparison with quart, pint, and cup

Imperial Gallon

It is a unit of measurement in the imperial system of units for both liquids and dry materials.

1 Imperial gallon $= 4.546092$ liters

                            $= 277.4196$ cubic inches

                            $= 4$ quarts

                            $= 160$ fluid ounces

Imperial gallon vs. US gallon

History of Gallon

Once upon a time, in the US, the volume of a gallon used to vary depending on:

  • the thing being measured
  • the location

In the British Empire, three definitions of gallon were very prevalent and included the following:

Ale Gallon 

During the reign of Queen Elizabeth I, the ale gallon was used as a unit of measurement for beers.

1 ale gallon $= 4.62115$ liters. 

Winchester Gallon

Sometimes known as the corn gallon, it was established by the English Parliament in 1696 to measure dry materials. The United States adopted the Winchester gallon post independence and it is now called the US dry gallon.

1 Winchester gallon $= 40488$ liters.                            

Wine Gallon

During Queen Anne’s reign in 1706, the wine gallon was used as a unit of measurement for wine. The United States adopted the wine gallon post independence and it is now called US liquid gallon.

1 wine gallon $= 3.78541$ liters.

After gaining independence from the British Empire in 1996, the United States adopted the wine gallon and Winchester gallon. The former is now called US liquid gallon, while the latter is now called US dry gallon.

On the other hand, the British Empire (now known as the United Kingdom) adopted the Imperial gallon in 1834. 

Uses of Gallon

1. In the US, gallon is most commonly used to measure fuel or gasoline.

Use of gallons in measuring gasoline

2. Other uses of a gallon include measuring and storing milk, paint, beer, oil, etc.

3. In the UK, it is unofficially used for economic or health purposes, such as to measure and store sanitizers. 

Fun Facts about Gallon

  • The Imperial gallon is 20 percent broader than the American liquid gallon.
  • The value of Imperial gallon in fluid ounces is 4 percent less than that of US liquid gallon in fluid ounces.
  • A gallon of milk weighs more than a gallon of water because of the fat content.


A gallon is a customary unit of volume for measuring liquids and sometimes dry materials. 

There are three different types of gallons: US liquid gallon, US dry gallon, and Imperial gallon. These three types are commonly used to measure and store fuel, oil, milk, paint, and many more things.

Solved Examples

1. Jen bought two gallons of milk. She wants to know the value of two gallons of milk in pints. 2 gallons $=$ ? pints. (according to the US standard of measurement). 


We know that 1 gallon $= 8$ pints.

So, 2 gallons $= 2 \times 8 = 16$ pints.

2. Determine 5 gallons $= \underline{}$quarts.

Solution: We know that 1 gallon $= 4$ quarts.

So, 5 gallons $= 5 \times 4$ 

                      $= 20$ quarts.

3. May wants to pour three gallons of wine into cups. Help her out by telling her how many cups she will need.


We know that 1 gallon $= 16$ cups.

So, 3 gallons $= 3 \times 16 = 48$ cups.

Thus, May will need 48 cups to completely pour in three gallons of wine.

4. How many water bottles is a gallon? (Assuming the volume of 1 bottle is 16.9 fl oz.)


We know that 1 gallon $= 128$ fluid ounces or fl oz.

To find the number of bottles in a gallon, we need to divide 128 fl oz by 16.9 fl oz.

$\frac{128}{16.9} = 7.57 = 8$ (approximately)

So, 8 water bottles make up a gallon.

5. Convert 10 gallons into fLuid ounces..


We know that 1 gallon $= 128$ fl oz

So, 10 gallons $= 10 \times 128$ 

                        $= 1280$ fluid ounces

Practice Problems


Attend this quiz & Test your knowledge.


Determine 20 gallons $= \underline{}$ cups.

Correct answer is: 320
Since 1 gallon $= 16$ cups
So, 20 gallons $= 20 \times 16 = 320$ cups

Tom needs to buy 56 pints of oil. He needs to place the order for oil in gallons. Help him out by finding how much 56 pints of oil are in gallons.

Correct answer is: 7
Since 8 pints $= 1$ gallon
56 pints $=$ ? gallons
To find the number of gallons, you need to divide 56 by 8.
$\frac{56}{8} = 7$.
So, Tom needs to place an order for 7 gallons of oil.

Pick the correct option.

9 gallons $= 26$ quarts
9 gallons $= 46$ quarts
9 gallons $= 56$ quarts
9 gallons $= 36$ quarts
Correct answer is: 9 gallons $= 36$ quarts
Since 1 gallon $= 4$ quarts.
So, 9 gallons $= 9 \times 4 = 36$ quarts.

Find 3 gallons $= \underline{}$ gills.

Correct answer is: 96
Since 1 gallon $= 32$ gills.
So, 3 gallons $= 3 \times 32 = 96$ gills

Frequently Asked Questions

What is the abbreviation of a pint?

The abbreviation of a pint is p or pt.

The symbol for quarts is qt.

The abbreviation for cups is c.

Liters are expressed in symbols as l or L.

The abbreviation for cubic inches is cu in, cu inch, or CI.

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