How the calculator works
Binding runs once around the quilt, so it starts from the perimeter. The calculator adds an allowance, then counts strips cut across the full width of the fabric.
- Perimeter = 2 × (quilt width + quilt length).
- Binding to make = perimeter + 12 inches.
- Length per strip = fabric width − strip width. A diagonal join uses up one strip width of length, so a 2 ¼-inch strip cut from 42-inch fabric adds 39 ¾ inches to the binding.
- Strips = binding to make ÷ length per strip, rounded up.
- Fabric = strips × strip width, rounded up to the next ⅛ yard.
Counting every strip a strip width short leaves one extra strip width spare over the whole binding. That is deliberate margin.
The 12-inch allowance is the top of the usual 10 to 12 inches. When you close the binding, the two tails overlap by one strip width before you sew them together on the diagonal. You need slack to make that join flat, and each mitred corner and the wrap over the batting take a little more. With a thick batting, use more.
Binding chart for standard quilt sizes
Based on 42 inches of usable fabric width, 12 inches of extra length and diagonal joins.
| Quilt | Finished size | Perimeter | Binding to make | 2 ¼ in strips | 2 ½ in strips |
|---|---|---|---|---|---|
| Crib | 36 × 52 in | 176 in | 188 in | 5 strips, ⅜ yard | 5 strips, ⅜ yard |
| Throw | 60 × 70 in | 260 in | 272 in | 7 strips, ½ yard | 7 strips, ½ yard |
| Twin | 70 × 90 in | 320 in | 332 in | 9 strips, ⅝ yard | 9 strips, ⅝ yard |
| Full | 84 × 90 in | 348 in | 360 in | 10 strips, ⅝ yard | 10 strips, ¾ yard |
| Queen | 90 × 108 in | 396 in | 408 in | 11 strips, ¾ yard | 11 strips, ⅞ yard |
| King | 108 × 108 in | 432 in | 444 in | 12 strips, ¾ yard | 12 strips, ⅞ yard |
If your fabric measures less than 42 inches between the selvages, pick the 40-inch width in the calculator. A narrower fabric can tip a quilt into an extra strip.
Example: binding a throw quilt
A throw quilt measures 60 × 70 inches after quilting and trimming, and you want 2 ½-inch strips from 42-inch cotton.
- Perimeter: 2 × (60 + 70) = 260 inches.
- Add 12 inches: 272 inches of binding to make.
- Each strip adds 42 − 2 ½ = 39 ½ inches once it is joined.
- 272 ÷ 39.5 = 6.89, so cut 7 strips.
- Seven strips × 2 ½ inches = 17 ½ inches of fabric, 0.49 yard. Buy ½ yard.
With 2 ¼-inch strips the quilt still needs 7 strips, but they use only 15 ¾ inches. A half yard covers it either way, so the narrower strip does not save you a cut.
Tips for cutting and sewing binding
- Measure after quilting. Quilting draws the quilt in, so measure the trimmed quilt, not the top you pieced.
- Square the fabric first. Fold it selvage to selvage and trim one edge straight before cutting strips. A shop cut can be a little crooked, so buy an extra ⅛ yard if your cut is close to the minimum.
- Join on the diagonal, then press open. Lay two strips right sides together at a right angle, sew corner to corner, trim to ¼ inch and press the seam open.
- Press the strip in half lengthwise, wrong sides together, before you sew it on. Double-fold binding is two layers thick along the edge, where quilts wear first.
- Start partway along a side, not at a corner, and leave a tail of about 10 inches at the start and end. The tails give you room to make the final diagonal join.
- Keep seams off the corners. Before sewing, walk the binding around the quilt and shift the start if a join lands at a corner, where it would make the mitre bulky.
Frequently asked questions
How many binding strips do I need for a queen-size quilt?
A 90 × 108 inch queen quilt needs 408 inches of binding, the 396-inch perimeter plus 12 inches for the corners and the final join. That is 11 strips cut across 42-inch fabric, either 2 ¼ or 2 ½ inches wide, which takes ¾ yard for 2 ¼-inch strips or ⅞ yard for 2 ½-inch strips.
Should binding strips be 2 ¼ or 2 ½ inches wide?
Both are standard for double-fold binding and practice varies. A 2 ¼-inch strip gives a narrower, firmer binding over thin cotton batting; 2 ½ inches is a little more forgiving and suits thicker batting. If you are unsure, bind a scrap sandwich of your own fabric and batting first.
How much extra binding do I need for the corners?
Allow 10 to 12 inches on top of the perimeter. The calculator uses 12 inches. The two ends overlap by one strip width when you close the binding, and the mitred corners and the wrap over the batting take up a little more.
Why join binding strips with a diagonal seam?
A 45° seam spreads the seam allowance along the strip, so there is no lump when the binding is folded and wrapped over the edge. It costs one strip width of length per join, against half an inch for a straight seam, and the calculator allows for that.
Do I need bias binding?
Only for curved or scalloped edges, where bias strips stretch to follow the curve. Straight edges bind well with strips cut across the fabric, which is what this calculator works out. Bias strips are cut at 45° from a square of fabric, so their yardage is figured differently.
Last updated October 17, 2026.