Quilt Calculator: Plan Your Whole Project from One Set of Measurements

Quilt Project Planner

How the planner works

Start with two numbers: the finished width and length of your quilt. Every other quantity on the shopping list is derived from them. Backing is the quilt top plus 4 inches of overhang on each side, so a 60 x 80 inch throw needs a 68 x 88 inch back — about 5 yards of 44/45-inch fabric with one vertical seam, or 2 1/2 yards of 108-inch wideback. Binding is the perimeter plus 10 to 12 inches for mitered corners and joining the ends: 2 x (60 + 80) + 12 = 292 inches, which works out to 8 width-of-fabric strips and 5/8 yard at a 2.5-inch cut width. Borders are figured like binding — perimeter-based strips — except they are cut wider, and their finished width gets added back into the quilt dimensions before you calculate backing and binding. Blocks work in the opposite direction: divide the finished top by the finished block size to see your grid, so a 60 x 80 quilt is exactly 48 blocks at 10 inches finished, six across and eight down. Order matters here. Settle the top dimensions first, borders included, then let backing, binding, and batting fall out of that final measurement rather than the pattern's starting size.

Standard quilt sizes at a glance

If you are not working from a pattern, start from a standard size. US quilters commonly cite these finished dimensions: baby around 30 x 40 inches, crib 36 x 52, lap 50 x 60, throw 50 x 65 (up to about 60 x 72 for a generous sofa quilt), twin 70 x 90, full or double roughly 80 x 90 up to 85 x 108, queen 90 x 95 up to 90 x 108, and king around 106 to 110 x 108. These are conventions, not rules. Bed quilt dimensions are really mattress dimensions plus a drop on three sides and, usually, a pillow tuck at the head — which is why published queen sizes span more than a foot. The ranges also change what the rest of the math looks like: a 50 x 65 throw needs one backing seam, a twin needs a full two-panel back or a wideback, and a king pushes binding past 440 inches. For a first quilt, the throw is the sweet spot — big enough to use, small enough to quilt on a domestic machine. Our quilt size chart page walks through the full chart, mattress-by-mattress, with the drop and tuck math for custom fits.

From pattern to shopping list

A pattern tells you the finished size and the fabric requirements for the top. It often leaves backing, binding, and batting as an exercise for the reader, and that is where a planner earns its keep. Work in this order. First, confirm the finished size — and if you are adding or dropping a border to resize, recalculate the true finished dimensions now. Second, take the top yardage from the pattern; for a typical pieced 60 x 80 throw, expect somewhere around 5 yards total across all top fabrics, more for intricate blocks with many seams. Third, compute backing: 68 x 88 means 5 yards of standard-width cotton or 2 1/2 yards of wideback. Fourth, compute binding: 292 inches means 8 strips, or 5/8 yard at 2.5 inches. Fifth, add insurance — an extra 1/4 to 3/8 yard on any fabric you cannot afford to run short on, since a miscut strip or a squaring-up pass eats fabric fast, and dye lots vary if you have to go back for more. Finally, round everything up to cuts a shop will actually make, typically 1/8-yard increments; rounding to the nearest 1/4 yard keeps the list simple and builds in a little margin.

Estimating the cost of a quilt

Quilting cotton in the US runs roughly $8 to $15 per yard — big-box and sale fabric at the low end, local-quilt-shop and designer lines at the top. Since a bed-size project consumes 10 to 20 yards all-in, the per-yard price you choose moves the total more than any other decision. Take the 60 x 80 throw as a worked example: about 5 yards for the top, 5 yards for backing, and 5/8 yard for binding is 10 5/8 yards. At $10 per yard, that is about $106 in fabric; the same list runs about $85 at $8 per yard and about $159 at $15. Add batting — packaged throw and twin sizes typically run $15 to $25, queen $25 to $35, king $30 to $45 depending on fiber — and thread, where one or two large spools of 50-weight cotton at $5 to $10 each will piece and quilt a throw. Realistic all-in for a throw: roughly $130 to $190, before any longarm quilting service. Two honest ways to trim it: put the inexpensive fabric on the back, where a 108-inch wideback can also beat pieced yardage on price per square inch, and save the $15-per-yard prints for the top where they show.

Planning mistakes that waste fabric

Forgetting shrinkage is the classic. Quilting cotton shrinks 3 to 5 percent in the first wash, so a 90-inch length can lose 3 to 4 inches. Either prewash everything or buy the small overage the calculator suggests — and never mix prewashed and unwashed fabrics in the same quilt, or they will crinkle unevenly. Ignoring waste is the second. Width-of-fabric strips rarely divide evenly into the pieces you need, squaring up trims an inch here and there, and one bad rotary cut can cost a whole strip; a 10 percent cushion on the top fabrics is standard practice, not padding. Directional prints are the third trap: stripes and motifs that have an obvious up require every piece to be cut in the same orientation, which blocks the efficient rotated layouts a calculator assumes — add extra, or choose a non-directional print. Fourth, measuring the mattress instead of the quilt: a queen mattress is 60 x 80, but a queen quilt is 90-plus inches wide once the drop and pillow tuck are added. Finally, buy each fabric in one trip. Dye lots shift between bolts, and the backing you top up three weeks later may not quite match the yardage already sewn in.