What are Fat Quarters, Charm Packs, Layer Cakes, Jelly Rolls, Strip sets? Basically, they are categoried as precuts, which are different precut bundles of quilting fabric.
Precuts are color coordinated and save you time because they are already precut.
Precuts are easy to work with and are a time saver. If you're a beginner quilter, the fabrics are all color coordinated and helps you to develop your eye for color values and contrasts.
As an experienced quilter, these precuts can help to develop a variety in your color choices. For example, I love brignt colors. When I walk into a quilt shop, I'm immediately drawn to the bright colors. So, when I wanted to make a quilt with more earthy tones, it was hard for me to choose the fabrics. Precuts helped me to 'see' a whole new range of colors. It was very helpful in developing my eye and choosing the earthy tones my quilt projects.
Let's sort this all out:
Fat Quarters
Technically, these are 1/4 of a yard of fabric, however, they are NOT the same as a 1/4 yard cut of fabric. I want to make that distinction. A fat quarter is approximately 18" x 22" (depends on length of fabric) a 1/4 yard of fabric is 9" x 44" (assuming the yardage is 44" wide). Fat Quarters will give you a wider section of fabric to work with, then a 1/4 yard cut. Be sure to request a fat quarter or a 1/4 yard cut when a Quilt shop is cuttng fabric for you.
Layer Cakes
Layer cakes are a bundle of 10" squares.
charm packs
Charm packs are a bundle of 5" squares.
Mini charm packs
Mini charm packs are a bundle of 2.5" squares.
Jelly rolls aka strip sets
Jelly rolls are also called Strip Sets. They are bundles of 2.5" x 44" (or 40" or 42" read the package) strips. The strip sets can also come in 1.5", 3", 5" or even 6" sets. Be sure to read the package for sizes and the number of strips included in the bundle.
Tips for Precuts
Do not prewash any precuts smaller than a fat quarter. The smaller pieces can stretch and fray during pre-washing, and you'll lose sizing on the strips/squares. Trust me on this one!
You can iron precuts before cutting. Be sure not to stretch the fabrics out of shape. Starch can help to stiffen the fibers and make the strips easier to work with.
Some of the precut bundles may have been cut with pinked edges (looks like a zig zag edge) to prevent fraying. Use the outermost of the pinking edge (the bumps) to gauge your 1/4 inch seam allowance. Don't line up your seam allowance with the valleys of the pinked edges. Trimming off the pinked edge is not recommended. If you decide to trim the pinking edge off, make sure the trimmed pieces will leave you with enough fabric to complete your project.
Read the package to know the number of strips/squares included in the pre-cut bundle. Also, the length (i.e., 44", 42" 40") of the strips will vary depending on the length of the mateiral used to cut the strips. So, be sure to check those dimensions to ensure that you buy enough to finish your project.
Happy Quilting!