How to Convert Cups to Gallons

Instructor: Artem Cheprasov
In this lesson, you're going to learn how to convert cups to gallons using the U.S. customary system of measurements, U.S. legal cups, and the British Imperial system of measurements.

Steps to Solve

Background Information

The cup in your kitchen cupboard may or may not actually be a cup. Meaning, it may or may not hold a volume of liquid that is actually equal to that of the unit 'cup'. A 'cup' is a unit of volume in the U.S. customary system. Gallons are also a unit of volume in the U.S. customary system of measurements.


To convert between the two, you need use the following easy steps.

Step 1:

Remember this conversion factor:

1 U.S. customary cup = 0.0625 U.S. gallons

Step 2:

Let's pretend that you are converting 100 cups to gallons. To do this, simply multiply the number of cups you have by 0.0625 like so:

100 cups x 0.0625 gallons/cup


100 cups x 0.0625 gallons/cup = 6.25 gallons

Different Conversion Factors and an Application

Note how the prior sections all used the U.S. customary system of measurement to convert from cups to gallons. However, there are other types of cups, including the U.S. and British Imperial cup. There are also British Imperial gallons. To convert between all of these, use the following conversion factors:

1 U.S. customary cup = 0.0625 U.S. gallons

1 U.S. customary cup = 0.0520 Imperial gallons

1 U.S. legal cup = 0.0634 U.S. gallons

1 U.S. legal cup = 0.0528 Imperial gallons

1 Imperial cup = 0.0751 U.S. gallons

1 Imperial cup = 0.0625 Imperial gallons


Let's say you live in the U.S. and just went to an antique store and bought a very old recipe book printed in Imperial Britain. The recipe book says that you need to use 3 cups of milk for something. You know that the book is using Imperial cups and not U.S. customary cups. Thus, you need to figure out how many cups of milk you actually need to use, given your U.S. measuring cups, before proceeding with the recipe. If you get it wrong, the recipe will be a disaster!

One way to solve this problem is to simply use a direct conversion factor:

1 Imperial cup = 1.2 U.S. customary cups

But this lesson is about converting cups to gallons not cups to cups. So we'll take the roundabout way of solving this problem to show that it can still be done using the conversion factors from the last section. First, you know that:

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account