Fat Quarter Calculator

What a fat quarter is, and why

A quarter yard cut normally is nine inches deep across the full 42 inch bolt width — a long, shallow strip that cannot yield anything more than nine inches in one direction. A fat quarter is the same area rearranged: half a yard cut off the bolt, then cut in half along the width, giving roughly 18 by 21 inches.

Same fabric, same price, far more useful shape. Anything needing a piece deeper than nine inches can come out of a fat quarter and cannot come out of a straight quarter yard, which is the entire reason the cut exists.

The exact size depends on the bolt. A 42 inch bolt gives 21 inches; a 44 inch bolt gives 22. That inch is often a whole extra row of small pieces.

A worked example

Five inch squares from an 18 by 21 fat quarter: three fit across the 18 inches, four down the 21, so twelve squares with a 3 by 21 strip left over.

A charm-pack quilt needing 60 five inch squares therefore takes five fat quarters, yielding 60 exactly. Ask for 2.5 inch squares instead and the same fat quarter gives 56, because seven fit across and eight down.

Where the answer misleads

The leftover strip is real fabric and usually gets forgotten. Planning cuts so the remainder is a usable width — a 2.5 inch binding strip, say — turns waste into stock.

Fat quarters are cut by hand in most shops and are frequently a little under nominal, particularly if the bolt end was not square. Measure before planning a cut that uses the full width, and plan to the smaller of the two dimensions if in doubt.

Directional prints halve the yield in the worst case, because pieces cannot be rotated. On a strong directional print, calculate with only the orientation that works.