Free tool
Quilt binding calculator
Enter your finished quilt size to calculate how many strips to cut and how much fabric to buy, with enough extra for mitered corners and joining the ends.
Selvages already removed.
12″ covers four miters and a join.
Planning the whole quilt? Start with the quilt fabric yardage chart and top estimator, then use this calculator for the binding itself. The straight-grain versus bias binding guide explains which method, strip width, join, and finish fit the project.
How much extra you actually need
The perimeter of the quilt is the starting point, but binding that measures exactly the perimeter will leave you short. Each mitered corner uses some length, and joining the two ends neatly takes several inches more. Ten to fifteen extra inches usually covers it comfortably; twelve is a sensible default.
The calculator also allows for the diagonal seams where strips are joined, which is why the yardage sometimes comes out a shade higher than a rough perimeter-divided-by-42 estimate.
Straight grain or bias?
Straight grain is appropriate for most quilts with straight edges and square corners. It's economical, quick to cut, and a straight edge does not require stretch.
Bias is cut at 45° so it stretches around curves without puckering. You need it for scalloped or curved edges, while some quilters also choose it for appearance or personal preference on straight quilts. It usually takes more fabric—the calculator switches to a square-of-fabric estimate when you choose it, since bias strips are cut diagonally across a square.
If you'd rather not bind it yourself
Many Utah shops that quilt tops will also finish the binding, and several run classes that cover it properly if you'd like to learn on someone else's machine first.