Quilt Calculator
Enter your finished quilt top dimensions and this calculator works out everything you need to complete the project: backing fabric in yards, binding yardage, batting size, and how much fabric to buy for a simple block-based top. Switch between inches and centimetres, set your fabric width, and see the step-by-step working behind every result.
How quilt backing yardage is calculated
Backing fabric must extend at least 3 to 4 inches beyond each edge of the quilt top to allow for shifting during quilting. This calculator adds your chosen overage to all four sides, then works out how many panels of your fabric need to be sewn together to cover that width. Each panel runs the full length of the backing. The panels are multiplied by the panel length to give a total cutting length, which is then divided by 36 (or 100 for metric) and rounded up to the nearest 1/8 yard (or centimetre) so you always buy enough. If your fabric is 108 inches wide, a single panel often covers most quilts without any seams at all.
Binding fabric: how to calculate strips and yardage
A standard double-fold binding uses strips cut 2.5 inches wide across the width of fabric (WOF). The total length of binding needed is the quilt perimeter plus about 20 inches for joining the strip ends and mitering the four corners. Divide that total by your fabric width to get the number of strips to cut. Each strip is 2.5 inches tall, so total fabric equals the number of strips multiplied by the strip width, rounded up to the nearest 1/8 yard. If you prefer a wider or narrower binding, adjust the strip width input and the calculator recalculates automatically.
Estimating quilt-top fabric
For a simple square-block top, the cut size of each block is the finished size plus two seam allowances (one on each side). This calculator works out how many cut blocks fit across your fabric width in a single strip, then divides the total block count by that number to find how many strips to cut. Total fabric in yards equals the number of strips times the cut block height, rounded up. The per-color figure assumes equal distribution across all colors, so if you plan an uneven layout, adjust accordingly.
Batting: sizing and buying the right amount
Batting needs to extend a few inches past the quilt top on every side, both to give you something to grip while quilting and to allow for any drawing-up during the quilting process. Three inches per side is a common minimum; this calculator defaults to that. If you are quilting on a longarm with a leader, check the longarm operator requirements, as many ask for 4 inches. Commercial batting is sold in packaged sizes (baby, twin, queen, king) and by the yard from a bolt. The batting size shown is the minimum raw dimension you need to buy or cut.
Common quilt sizes and backing panels
| Quilt size | Finished dimensions | Backing panels (44 in WOF) | Batting size |
|---|---|---|---|
| Baby | 36 x 52 in | 1 panel | 42 x 58 in |
| Throw | 50 x 65 in | 2 panels | 56 x 71 in |
| Twin | 60 x 80 in | 2 panels | 66 x 86 in |
| Full/Double | 80 x 90 in | 3 panels | 86 x 96 in |
| Queen | 90 x 108 in | 3 panels | 96 x 114 in |
| King | 108 x 108 in | 3 panels | 114 x 114 in |
Approximate finished dimensions for standard quilt sizes and the number of 44 in backing panels typically needed.
Frequently asked questions
How much backing fabric do I need for a 60 x 80 in quilt?
With a 44 in wide fabric and 4 in of overage on each side, you need a backing that is at least 68 x 88 in. That requires two panels, each 88 in long, giving 176 inches total, which rounds to 4 7/8 yards. Enter your exact dimensions above and the calculator shows the precise figure for your fabric width.
How do I calculate binding yardage?
Add the four sides of your quilt together (the perimeter), add about 20 extra inches for corner miters and joining the strip ends, then divide by the width of your fabric to find how many 2.5 in strips to cut. Multiply the number of strips by 2.5 in and convert to yards. For a 60 x 80 in quilt the perimeter is 280 in; add 20 and divide by 44 gives 7 strips, or 7 x 2.5 = 17.5 in, which rounds up to 5/8 yard.
What size batting do I need?
Buy batting that is at least 6 inches wider and 6 inches longer than your finished quilt top (3 inches extra per side). For a 60 x 80 in quilt, that means a minimum of 66 x 86 in. Standard packaged batting sizes often exceed this, so choose the next size up. If the packaged size is close, confirm it covers your minimum before cutting.
How many blocks do I need for a quilt?
Divide the quilt width by the finished block size (rounding up) and do the same for the length, then multiply those two numbers. A 60 x 80 in quilt using 12 in blocks needs 5 across and 7 down, giving 35 blocks total. This calculator works it out for you once you enter the quilt size and block size.
How wide should binding strips be?
The most common width for double-fold straight-grain binding is 2.5 inches, which produces a binding about 1/4 to 3/8 inch wide on the front of the quilt when sewn at a 1/4 in seam. Cut them wider (up to 3 or 3.5 in) for a chunkier binding or if you want extra coverage for thick batting. The strip width input in this calculator lets you try different widths and see how the yardage changes.
What is WOF in quilting?
WOF stands for width of fabric, meaning the full usable width from selvedge to selvedge after removing any non-printed edges. Standard quilting cotton is typically 42 to 44 inches WOF. Wide-back backing fabric is 108 to 118 inches. Minky and flannel run around 58 to 60 inches. Always measure your actual fabric and enter the real WOF in the calculator.
Should I pre-wash my quilt fabric?
Most quilters pre-wash cotton fabrics because quilting cotton can shrink 2 to 3 percent on the first wash. If you skip pre-washing, consider buying an extra 1/8 to 1/4 yard per fabric to account for shrinkage, and be aware the finished quilt may pucker slightly after its first wash, which some quilters prefer for a vintage look.