Squares per yard.

Answer

200 squares cut 2.5 in from fabric 40 in wide need 13 strips, 32.5 in of fabric, which is 0.90 yd and rounds up to 1 yard. Each strip gives 16 squares.

Worked example

Squares per strip = whole squares across 40 in = 40 / 2.5 = 16. Strips = 200 / 16 = 12.5, rounded up to 13. Fabric length = 13 x 2.5 = 32.5 in = 0.903 yd, so buy 1 yd. Squares to spare: 13 x 16 - 200 = 8. Going the other way, 1 yd (36 in) gives 36 / 2.5 = 14 strips (whole strips only), so 224 squares.

How it works

Strips are cut across the width of the fabric, one square tall. Each strip is then cut into squares, and only whole squares count. Strips needed = squares / squares per strip, rounded up; fabric length = strips x cut size; yards = inches / 36, rounded up to the next 1/8 yard so you are not short. Ask your shop which increment it cuts. Selvage trimming and fabric width vary, so measure your usable width rather than trusting the label. This is plain arithmetic; add extra if your fabric has a directional print or you want a margin for squaring up.

FAQ

How many 2.5 inch squares can I cut from a yard of fabric?

From 40 in usable width you get 16 squares per strip and 14 whole strips from a 36 in yard, so 224 squares of 2.5 in.

How much fabric do I need for 100 squares?

It depends on the square size and fabric width. Enter both above: for example 100 squares of 2.5 in from 40 in fabric need 7 strips, which is 17.5 in of fabric.

Why does the calculator round up to 1/8 yard?

So you are not short. Check which increment your shop cuts in, since not every shop cuts to 1/8 yard.

What width should I enter?

The width you can actually use, measured after trimming the selvage edges. It is the labelled width minus whatever you trim.

Does it allow for seam allowances?

Enter the cut size, which already includes seam allowances. A square that finishes 2 in is cut 2.5 in with a 1/4 in seam.