Quilting Square Cutting Calculator

Each square needs a seam allowance added to all four sides. Standard 1/4 inch seam means adding 1/2 inch total to each dimension. A 6-inch finished square needs to be cut at 6.5 inches. For triangles (half-square triangles), add 7/8 inch to each side before cutting the diagonal. Always cut generously - better to have extra than to come up short.

For half-square triangles (two squares sewn together on diagonal), begin with unfinished triangle size. For a finished 2-inch half-square triangle when sewn: start with 2.875 inch squares (3.875 + 3.875 = 7.75 total, cut on diagonal = two triangles). The formula: starting size = finished + 7/8. Sew up, square to finished size at 2 inches.

Binding requires additional fabric for the border. Calculate perimeter of quilt, add 10 inches for corners and overlap. Divide by 42 inches (standard binding width from fat quarter). Example: 60x80 inch quilt = 280 inch perimeter + 10 = 290 inches / 42 = 6.9, round up to 7 strips about 2.5 inches each for double-fold binding.

A fat quarter is 18x22 inches. For 2.5 inch squares (including 1/4 inch seam): from 18-inch side get 7 squares (18/2.5 = 7.2), from 22-inch side get 8 squares (22/2.5 = 8.8). So 56 squares total. Adjust proportionally for different final square sizes.