Quilt backing calculator
Enter your quilt size and get the yardage, how many pieces to cut and where the seams go.
What size quilt does my bed need?
Pick your mattress and how far you want the quilt to hang. You get the finished size, plus the backing, binding and batting that size needs.
How it's worked out
Finished width is the mattress width plus the drop on both sides. Finished length is the mattress length plus the drop at the foot and the pillow tuck. A coverlet drops the mattress depth plus 3", a comforter the depth plus 9". Batting is cut 4" bigger than the quilt on every side, so we suggest the smallest common batting size that covers that.
How much fabric for quilt backing?
Enter your quilt top size. We work out the backing in both seam directions and tell you which one uses less fabric.
How it's worked out
We add your extra to every side, so a 60 × 72" quilt with 4" extra needs a 68 × 80" backing. Standard cotton is about 42" wide once the selvages are trimmed, so wider backings are pieced from panels joined with ½" seams. We check seams running top to bottom and side to side, and recommend the one that needs less fabric. Yardage is rounded up to the next ⅛ yard.
How much fabric for quilt binding?
Enter the quilt size and your strip width. You get the number of strips to cut and the yardage to buy.
How it's worked out
Binding runs around the whole edge, so you need 2 × (width + length) plus your extra. Strips are cut across the fabric width and joined with diagonal seams. Each join uses up about one strip width of length, and we allow for that. Fabric is the number of strips times the strip width, rounded up to the next ⅛ yard.
How much fabric for quilt borders?
Measure your quilt top through the middle and enter the finished border width. Adding more than one border? Work out the first, then tap “Add another border”.
How it's worked out
Strips are cut ½" wider than the finished border, to allow for seams. For butted borders the sides are cut to the quilt length, and the top and bottom to the width plus both side borders. For mitered borders every strip is its side plus two border widths plus 3" to spare. Strips cut across the fabric are joined end to end when a side is longer than the fabric is wide. Strips cut along the length need no joins but use more fabric.
How many blocks, and how much fabric?
Enter the size you want and your finished block size. You get the layout, the true finished size, and fabric for simple squares, fat quarters and precuts.
How it's worked out
We choose the number of blocks across and down that comes closest to your size, then show the exact size you'll get. Squares are cut ½" larger than finished for ¼" seams. Fabric is the number of strips you need, each as tall as one square. Fat quarters are counted as 18 × 21". Charm packs and layer cakes are counted as 42 squares of 5" and 10".
What size squares for half-square triangles?
Pick the finished size, how many you need and your method. You get the square size to cut, how many squares, and fabric for each of the two colours.
How it's worked out
Two at a time: cut squares the finished size plus ⅞", sew ¼" either side of the diagonal, and cut on the line. Four at a time: sew around all four edges and cut both diagonals; squares are (finished + ½") × 1.414 + ½". Eight at a time: sew ¼" either side of both diagonals; squares are 2 × (finished + ⅞"). The trim option adds a little so you can square each one up to the finished size plus ½".
Results are rounded up so you won't run short. Fabric shrinks and quilt tops stretch, so measure your own top before you cut. Many quilters buy an extra ¼ yard to be safe.
Want the whole quilt worked out?
The Quiltkind studio plans every block, border and binding at once, from the fabric you already own, and walks you through each cut.
Plan the whole quilt before you cut
The Quiltkind studio is in early testing. It does what these calculators can't:
- Photograph your fabric on your cutting mat and see it at its true print size
- Plan from what you already own: yardage, fat quarters, charm packs and scraps
- Get a waste-saving cutting plan, then tick off each cut at the cutting table
- Check contrast in black and white before you sew a seam
Join the early list. Your answers decide what we build first.