Originally Posted by
katier825
About 18x22. Should always be 18. The other can vary by width of the fabric.
Katier825 is right. A fat quarter is 1/2 yard long (36 inches divided by 2 = 18 inches) and then 1/2 the width of the fabric. Most quilting cottons are 42-44inches wide, so the fat quarter will be half of that, or 21-22 inches.