Quilt binding & border calculator
Running short of binding mid-project is a classic frustration. Know how much fabric to buy before you get to the shop, not after. Type in your quilt size and strip width and get the strip count and yardage, with borders and sashing a checkbox away, and the cutting math shown rather than hidden, so you can check it yourself. It runs in your browser: no email, no download, nothing sent anywhere. For blocks, backing and the whole quilt, use the yardage calculator.
Binding a 60 by 72 inch throw with 2.5 inch strips from 40 inch usable cotton: perimeter 264 inches plus 10 inches is 274 inches, which is 7 strips and 0.5 yards.
- Runs in your browser
Your quilt
The quilt top before any border. Sashing is already inside this size.
The cut width. 2.25 in is common for double-fold; 2.5 in suits thicker quilts.
Used for border and sashing cut widths.
Width after trimming selvages. Quilting cotton is usually about 40 in.
binding length — — finished size —
| Element | Cutting | Buy |
|---|---|---|
| Binding | — | — |
| Border | — | — |
| Sashing | — | — |
Total to buy yards
A worked example
Say you're binding a 60 × 72 inch throw with 2.5 inch strips from standard quilting cotton with 40 usable inches of width. Here's exactly what the calculator does with that:
- Binding length. The perimeter is 2 × (60 + 72) = 264 inches, plus 10 inches for joins and mitered corners: 274 inches.
- Strips. Each strip runs the full fabric width, so 274 ÷ 40 = 6.85, which rounds up to 7 strips.
- Yardage. 7 strips × 2.5 inches = 17.5 inches = 0.49 yards, which rounds up to 0.5 yards.
How the math works
Nothing here is a mystery. These are the formulas, so you can check any number by hand:
- Binding: the finished perimeter (after any border) plus 10 inches for joins and mitered corners, cut into strips of your chosen width across the fabric. Strips = length ÷ fabric width, rounded up.
- Border: strips are cut at finished border width + 2 × seam allowance. The two side borders run the quilt's height; the top and bottom run the full bordered width. Total length ÷ fabric width, rounded up, gives the strip count (joins land in the leftover).
- Sashing: strips are cut at finished sashing width + 2 × seam allowance, continuous with no cornerstones. Vertical pieces: blocks across minus one, per row, each one block high. Horizontal rows: blocks down minus one, each running the full quilt width. The block size is worked back out of the quilt size you typed in, since the sashing sits inside it.
- Everything rounds up to the nearest quarter yard per element, because that's how shops cut, and the total is the sum of those rounded pieces. The yardage calculator does the same, so the two tools always agree.
Double-fold or single-fold?
The 2.5 inch default assumes double-fold (French) binding on a quilt of ordinary to thick loft: the strip is pressed in half lengthwise before it goes on, so the quilt edge gets two layers of fabric. That's the usual choice for anything that will be washed and used, because the fold takes the wear instead of a single raw-edged layer. Single-fold binding uses a narrower strip and puts one layer on the edge; it suits wall hangings and miniatures where bulk matters more than durability. The calculator only prices the strip width you give it, so if you switch to single-fold, cut narrower and type that number in.
Working out the rest of the quilt? The yardage calculator does blocks, backing, borders and binding together from your quilt and block size.
Questions
How wide should binding strips be?
For double-fold binding, Utah State University Extension gives 2.25 inches as the common width and 2.5 inches for thicker quilts. This calculator starts at 2.5, so a quilt with a puffier batting still has enough fold to wrap the edge; type 2.25 if your quilt is thin. Whatever width you choose, type it in: the strip count stays the same, only the yardage changes.
Bias binding vs straight-grain: does this calculator handle bias?
It assumes straight-grain strips cut selvage to selvage across the fabric width, which is how most quilters bind a straight-edged quilt. Bias strips are cut at 45 degrees, so the yield per yard is different and depends on how you cut them. If your quilt has curved edges and needs bias binding, treat this calculator's number as the length you have to make, not the yardage to buy, and plan the bias cuts on paper.
Why add 10 inches for joins?
Each mitered corner folds away a little length, the diagonal seams that join strips overlap, and you need tails left over to close the final join neatly. Ten inches covers all of that on a typical quilt. It's the same allowance our yardage calculator uses, so the two tools give the same binding answer for the same quilt.
Does it add a just-in-case buffer?
Only two allowances, and both are visible in the math: the 10 inches added to the binding length for joins and corners, and the round-up to the nearest quarter yard on each element, because that's the smallest cut shops sell. There is no hidden percentage on top. If you want slack for a miscut or prewashing, add it yourself and you'll know exactly how much you added.
Can I calculate sashing without cornerstones?
That's exactly what this calculates: continuous sashing with no cornerstones. Short vertical pieces separate the blocks in each row, and unbroken horizontal strips run the full quilt width between rows. If you want cornerstones, the horizontal strips become short pieces one block wide, and the squares where they meet come from your cornerstone fabric instead; you'd need one square per crossing, which is blocks-across minus one, times blocks-down minus one.
What about directional fabric for borders?
Buy extra. The strip math assumes any strip can rotate to fit, and a directional print can't: cuts have to follow the print, so side borders and top borders may need cutting in different directions and you lose more to offcuts. Same guidance as our yardage calculator: plan the cuts on paper first and treat the calculated number as the minimum, not the target.
Updated