How Many Fat Quarters Do I Need to Make a Quilt?

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Fat quarters are 18″ x 22″ rectangle cuts of fabric that are very popular among quilters. The name is a bit silly, but it’s quite descriptive. A regular quarter yard of fabric is cut in a long 9″ x 42″ strip, but a fat quarter is a quarter yard of fabric cut in an 18″ x 22″ rectangle. Rather than the yard being cut into 4 strips, it’s cut into 4 rectangles.

Fat quarters are typically sold in individual packages or in curated fat quarter bundles. There is no standard number of fat quarters in a bundle, so you can expect to find bundles of anywhere from 5 to 25 fat quarters (and sometimes more!).

Fat quarters are popular among quilters because they are a generous size for a precut fabric and allow for a lot of pieces to be cut from one piece. Another appeal is that they are sold in curated bundles which takes the guesswork out of choosing fabric for a quilt. Quilts made from fat quarter bundles have a scrappy look but are still cohesive.

But how do you determine how many fat quarters you’ll need for your project? Let’s find out.

Before you can determine how many fat quarters you’ll need for a project, you’ll need to figure out how large your quilt will be. If the quilt you’re making is meant for a bed, you can use the mattress size. Remember to add several inches if you want the quilt to hang off of the bed. 

Check out my free printable quilt size chart if you need a refresh on quilt sizes!

If your quilt is not meant for a bed, you can be more flexible with your measurements and use some of the suggested sizes that I have listed in my examples below.

After you have your desired quilt size, you can calculate how many fat quarters you need for your quilt, or you can use my example calculations to get a general idea of how many you’ll need.

My example calculations are using full 18″ x 21″ fat quarters (minus ¼” seam allowance on all sides). After removing 1/2″ for the seam allowances, the finished rectangle size will be 17.5″ x 20.5″. Most of the time a fat quarter is cut into smaller pieces, so keep in mind that these calculations are only an estimate and if you plan to cut the fat quarter you will need to account for that when purchasing fabric.

My calculations do not account for pieced blocks, sashing, or borders. If you want to cut into your fat quarters, add sashing, or add borders, you’ll need to adjust these calculations.

Please use my calculations for reference only, and be sure to double-check your quilt math before you go shopping for fabric!

Want to save this information for later? Download the free Fat Quarters in a Quilt Cheat Sheet!

How Many Fat Quarters Does it Take to Make a Baby Quilt?

In order to make a 35” x 41” baby quilt, you will need 4 fat quarters.

Keeping the fat quarter in one piece is a great way to highlight large print fabric or make a quick and easy baby quilt.

How Many Fat Quarters Does it Take to Make a Throw Size Quilt?

To make a 52.5” x 61.5” throw quilt, you will need 9 fat quarters.

How Many Fat Quarters Does it Take to Make a Twin Size Quilt?

To make a 70” x 82” twin-size quilt, you will need 16 fat quarters.

How Many Fat Quarters Does it Take to Make a Full Size Quilt?

Just like the twin-size quilt, in order to make a
70” x 82” full-size quilt, you will need 16 fat quarters.

Because of the fat quarters’ size, it’s not possible to size a quilt up or down in smaller increments unless you cut the fat quarter.

In this post, I am doing the math for full fat quarters, so the twin and full-size quilts are the same size.

How Many Fat Quarters Does it Take to Make a Queen Size Quilt?

To make an 87.5” x 102.5” queen size quilt, you will need 25 fat quarters

How Many Fat Quarters Does it Take to Make a King Size Quilt?

To make a 105” x 102.5” king size quilt, you will need 30 fat quarters.

What Size Quilt Can You Make With 9 Fat Quarters?

The largest quilt you can make with 9 fat quarters is a 52.5” x 61.5” size quilt.

Arrange the fat quarters in a 3×3 grid to achieve this size of quilt.

What Size Quilt Can You Make With 12 Fat Quarters?

The largest quilt you can make with 12 fat quarters is a 52.5″ x 82″ size quilt.

Arrange the fat quarters in a 3×4 grid to achieve this size of quilt.

What Size Quilt Can You Make With 16 Fat Quarters?

The largest quilt you can make with 16 fat quarters is a 70” x 82” size quilt.

Arrange the fat quarters in a 4×4 grid to achieve this size of quilt.

What Size Quilt Can You Make With 20 Fat Quarters?

The largest quilt you can make with 20 fat quarters is a 70″ x 102.5″ size quilt.

Arrange the fat quarters in a 4×5 grid to achieve this size of quilt.

How to Calculate How Many Fat Quarters Are Needed For a Quilt

If you want to do your own math, here’s how to do it.

Before we do any calculations we need to subtract the seam allowance from our fabric. The standard seam allowance for quilting is ¼ inch. Because there will be seams on every side of our fat quarter, we need to subtract two seam allowances from our starting measurement of 18″ x 21″. That leaves us with a finished square size of 17.5″ x 20.5″.

Now that we have the size of our fat quarter blocks, we can divide our finished quilt dimensions by 17.5″ x 20.5”.

Let’s do a quick example:

We want to make a baby quilt. According to these quilt size guidelines, a good baby size quilt is 30″ x 40″. We’ll base our measurements on that guideline.

To determine the number of fat quarters needed we’ll divide 30” / 17.5” to get 1.71. Because we don’t want a partial square, we’ll round that up to 2. We will need 2 fat quarters to reach our quilt width of roughly 30”. The width will technically be 35″ (2 x 17.5).

Now let’s do the length. We’ll divide 40” x 20.5” to get 1.9. Again, we’ll round up to 2. We will need 2 fat quarters to give us a roughly 40″ quilt length (41″ to be exact).

Now we’ll multiply the number of squares together. 2 x 2 = 4 fat quarters. For a 35″ x 41″ quilt we need 4 fat quarters.

HELPFUL TIP: When calculating how many fat quarters you need for a quilt be sure to account for any sashing or borders you may want to add. For example, if you want a 4-inch border around your quilt, subtract your desired quilt size by 8” to account for your borders BEFORE you calculate how many fat quarters you need.

Fat Quarter Quilt Size Chart

Below is a chart that shows the largest quilt you can make with full 18″ x 21″ fat quarters.

Now you know how to figure out exactly how many fat quarters you need to make your next quilt. Grab a fat quarter bundle and get started!

Remember to download the free cheat sheet so you can save this information for later!

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The Stress-Free Guide to Machine Washing Your Quilt
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