Batting Size Calculator

Batting should be a little larger than the quilt top so the layers can shift slightly during quilting and still cover the whole quilt. Enter your quilt size and the overhang you want, and the calculator gives the batting size to look for on a package.

4 in is a common default.

Only if you buy batting by the yard. Leave blank for packaged batting.

Batting size: 58 x 73 in.

From a roll90 in wide
Pieces1 x 58 in
Length to buy58 in (1 5/8 yd)

Packaged batting: choose a package at least this size in both directions.

If you buy batting by the yard from a roll, enter the roll width as well. The calculator works out whether one length covers the quilt, and if not, how many pieces to butt together and how much to buy.

Worked example: batting for a throw quilt

A 50 x 65 in throw with 4 in of overhang, from a 90 in wide roll.

  1. Batting size: 50 + 8 = 58 in by 65 + 8 = 73 in.
  2. Buy a package at least 58 x 73 in, checking both directions on the label.
  3. From a 90 in roll the batting fits in one piece. Turning it so the 58 in side runs along the roll means cutting 58 in.
  4. 58 in / 36 rounds up to 1 5/8 yd.

Result: 58 x 73 in of batting, or 1 5/8 yd from a 90 in roll.

How batting size is calculated

  1. Batting width = quilt width + 2 x overhang. Batting length = quilt length + 2 x overhang.
  2. From a roll: if one side of the batting fits the roll width, buy one length equal to the other side (the shorter of the two options).
  3. If neither side fits, the batting is pieced: pieces = batting width / roll width, rounded up, each as long as the batting (or the same turned 90 degrees, whichever needs less).
  4. Yards = total length / 36, rounded up to the next 1/8 yard.

Assumptions

  • Overhang is 4 in per side by default. Longarm quilters often ask for 4 to 6 in, the same as the backing; check with yours.
  • Package sizes vary by brand and are printed on the label. The calculator does not assume any brand sizes.
  • Some batting shrinks when washed; cotton batting typically shrinks more than polyester. That changes the finished quilt, not the size to buy.

Frequently asked questions

How much bigger should batting be than the quilt top?

4 in on every side is a common rule, so 8 in wider and 8 in longer than the top. If a longarm quilter is finishing it, follow their requirement; many ask for 4 to 6 in per side.

What size batting do I need for a king quilt?

For a 108 x 108 in king with 4 in overhang, the batting is 116 x 116 in. From a 90 in roll that is 2 pieces of 116 in butted together, 6 1/2 yd in all.

Can I piece batting together?

Yes. Butt the straight edges together without overlapping and join them with a wide zigzag stitch or fusible batting tape so the join stays flat.

Which batting should I choose?

That depends on warmth, loft, drape and how the quilt will be used. The QuiltLab batting guide and batting selector compare materials side by side.

Design the quilt, then do the math

Sketch blocks and lay out your quilt in QuiltLab, then come back to these calculators for cutting and yardage.

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