How many fat quarters do I need for a quilt top?

Often I find myself purchasing a fat quarter bundle and then designing a quilt that fits the amount of fabric I have to work with. I don't like to have a lot of scrap fabric left over so I try to make the biggest quilt that the bundle I purchased allows for. Different bundles come with different amounts of fabric.

What is the minimum number of fat quarters I need for a quilt top? | Have you ever bought a fat quarter bundle without a quilt pattern in mind for it ahead of time? Raise your hand then click through for an easy chart that tells you how many fat quarters you need at a minimum for each standard quilt size.

I made myself a little cheat sheet so that I can estimated what size quilt I'm going for based on how many fabrics are in my fat quarter bundle.

What is the minimum number of fat quarters I need for a quilt top? | Have you ever bought a fat quarter bundle without a quilt pattern in mind for it ahead of time? Raise your hand then click through for an easy chart that tells you how many fat quarters you need at a minimum for each standard quilt size.

This cheat sheet assumes that you use the fat quarters whole with 1/4 seam allowance. It's not a realistic way to make a quilt as it doesn't account for selvedges. It's just a place to start estimating from.

  • You're probably going to want to cut up your fat quarters into smaller pieces. Every time you cut you need a little bit more fabric to account for additional seam allowance.
  • There might be fabrics you don't like or might not want to use as much of.
  • If you don't have enough fat quarters for the quilt top you want to make, mix in some coordinating solids or neutrals. Half prints from a fat quarter bundle + half white is one of my favorite fabric combos.
  • If you've got more fat quarters than you need for the quilt top you want to make, you can work extras into the backing or binding.

Notice that Queen and Double (Full) size need the same number of fat quarters. Places like Pottery Barn usually don't even differentiate between the two sizes.

I'd like to do the math

Here's what you need to know to get started:

  • What size battings are available to you. I've got a cheat sheet for that here.

  • How much overage you want around the edge of your quilt top when you sandwich it with the batting and backing. I like 2 inches on each edge, 4 inches total for the width and 4 inches total for the length.
  • The size of a fat quarter. I used 22 inches wide, 18 inches long, and a 1/4 inch seam allowance. You could knock that down to 20 by 16 if you want to be more conservative with selvedges.

Here's how to do the math:

  1. Width of the batting - your overage = A
  2. Length of the batting - your overage = B
  3. A / (width of your fat quarter - 2x seam allowance)
  4. round your answer to 3 up to the next whole number and call that C
  5. B / (length of your fat quarter - 2x seam allowance)
  6. round your answer to 5 up to the next whole number and call that D
  7. C * D = the total number of fat quarters you need at a minimum