Enter your quilt dimensions to estimate how much fabric to buy for backing, binding or borders. Use inches or centimeters and see how to cut the pieces.
How to use this quilt calculator
Pick a tab, choose your quilt size or type it in, and the amount to buy appears straight away. Everything is rounded up to the next ⅛ yard so you don't come up short. Switch between inches and centimetres at any time.
How much backing fabric do I need for a quilt?
Backing should be larger than the quilt top. Most quilters add about 4 inches on each side, so 8 inches in total, which gives room for quilting and trimming. If you plan to have the quilt longarmed, ask your quilter, as many want 4 to 6 inches extra on every side.
Standard quilting cotton is 44 to 45 inches wide, but only about 42 inches is usable once you trim the selvages. Most quilts are wider than that, so the backing has to be pieced. The calculator tests both directions (seams running top to bottom, or across) and shows the one that uses less fabric. A 108-inch wide backing fabric often fits in one piece. Measure the usable width before buying.
| Quilt (typical size) | Backing size (4 in extra per side) | Approx. yardage, 42 in usable fabric |
|---|---|---|
| Baby, 36 × 52 in | 44 × 60 in | 2½ yd |
| Queen, 90 × 95 in | 98 × 103 in | 8¼ yd |
Quilt sizes vary by pattern, so treat these as examples, not rules.
How much binding do I need?
Add the four sides and allow 10 inches for turning corners and closing the binding. The calculator also deducts one strip width for each diagonal join. A 90 × 95 in quilt with 2½ in strips needs ⅞ yd at 40 in usable fabric width or ¾ yd at 42 in usable width.
How much border fabric do I need?
Cut each border strip ½ inch wider than the finished border, which covers the seam allowance on both sides. For straight corners, the side borders match the quilt's length and the top and bottom borders are the quilt's width plus the two finished side borders and ½ inch for seam allowances. Mitered corners need extra length on every side, so the calculator adds 4 inches of spare.
Frequently asked questions
Why does the calculator say to buy more than the exact amount?
Fabric is sold in set fractions of a yard, and fabric can shrink, skew or be cut off-grain. The calculator rounds up to ⅛ yard. Allow additional fabric for shrinkage, squaring up or matching a print.
Should I prewash my fabric?
If you prewash, buy a little more, since fabric can shrink 2 to 5 percent. If you skip prewashing, make sure all fabrics in the quilt are treated the same way.
Is the usable width really 42 inches?
Most 44/45 inch quilting cotton gives 40 to 42 inches once the selvages are trimmed. Use 40 if you want to be cautious.
Does this work for rag quilts, hexagons or irregular shapes?
No. The calculator assumes a rectangular quilt. For other shapes, treat the overall width and length as a bounding rectangle and add extra for wasted fabric.