Fat quarters are pre-cut pieces of fabric that are 1/4 of a yard. They are usually folded like this at the quilt shop for easy display. They are also pre-cut into bundles of coordinating fabrics when buying online. The difference is that it is not cut in the traditional way that fabric has always been cut.
Both pieces measure 1/4 of a yard. The traditional cut is skinny compared to the new cut which is "fat". Depending on the project, the fat quarter can provide a more usable piece of fabric.
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31 Days of Raising Teens