How Much Fabric Do I Need to Cut Squares?
Squares are the simplest shape in quilting, and patchwork quilts can use dozens or hundreds of them. Working out the fabric is a three-step calculation.
Step 1: squares per strip
Cut a strip across the width of fabric as wide as your square. With about 42 inches usable, divide 42 by the square size and round down: a partial square at the end of the strip is waste.
Step 2: number of strips
Divide the number of squares you need by the squares per strip, and round up to a whole strip.
Step 3: fabric
Multiply strips by the strip width to get inches of fabric. Divide by 36 for yards and round up to the next 1/8 yard.
Worked example: 40 squares at 5 inches
- Squares per strip: 42 / 5 = 8.4, so 8.
- Strips: 40 / 8 = 5.
- Fabric: 5 x 5 = 25 inches, which rounds up to 3/4 yard.
Worked example: 100 squares at 2 1/2 inches
- Squares per strip: 42 / 2.5 = 16.8, so 16.
- Strips: 100 / 16 = 6.25, so 7.
- Fabric: 7 x 2.5 = 17.5 inches, or 1/2 yard.
Worked example: 20 squares at 10 1/2 inches
- Squares per strip: 42 / 10.5 = 4 exactly.
- Strips: 20 / 4 = 5.
- Fabric: 5 x 10.5 = 52.5 inches, which rounds up to 1 1/2 yards.
In the last example the squares fit the fabric width exactly. If your fabric turns out to be slightly narrower than 42 inches after trimming, you would only get 3 squares per strip and need 7 strips instead. Measure your fabric and enter the real width if you are cutting close.
Cut size, not finished size
These numbers use the size you cut. If your pattern lists finished squares, add 1/2 inch for the 1/4 inch seam allowance on each side: a 4 inch finished square is cut at 4 1/2 inches.
Precuts
Pre-cut 5 inch and 10 inch squares and 2 1/2 inch strips can save cutting time. Check how many pieces are in the pack against the count you need, and remember that precut edges are sometimes pinked, which affects your seam allowance.
Frequently asked questions
Should I buy extra?
The calculation has no margin for a mis-cut or for straightening the fabric edge. Many quilters add an extra strip, or round up to the next quarter yard, especially for a fabric they can't easily buy again.
What if I need squares in several fabrics?
Run the calculation once for each fabric with its own count. Squares from different fabrics don't share strips, so adding the counts together first would underestimate the fabric.
Can I use fat quarters?
A fat quarter measures about 18 x 21 inches, so strips cut along the 21 inch side give fewer squares per strip. Work out squares per strip using 21 instead of 42, and count how many strips fit in 18 inches.
Does this work for rectangles?
Yes: cut strips as wide as one side of the rectangle and divide 42 by the other side to get pieces per strip, then follow the same steps.
Calculate any quantity
The squares yardage calculator does the arithmetic for any square size, quantity and fabric width. Add the result to the fabric requirements worksheet in The Quilt Planner to build a full shopping list.
Related tool: open the calculator.