Quilt Batting Calculator

Enter your quilt top size. You get the batting size with overhang, the smallest standard package that covers it, and the cut off the roll when a package doesn’t fit.

Your Quilt

Batting Needed

56 × 71in

for your 50 × 65 in top at 3 in overhang

  • Batting size needed56 × 71 in
  • Smallest package that fitsTwin (72 × 90 in)
  • Off the roll instead2 yd off a 90 in roll (71 in cut)
  • Leftover strip from the package16 in × 90 in

The Formula

batting size = quilt top + 2 × overhang in each direction

Batting needs less margin than backing: longarm clamps grip the backing, and the batting only has to outreach the top. Three inches per side covers most work; match your backing overhang if your longarmer asks.

Worked Example

A 50 × 65 in throw with 3 in overhang needs 56 × 71 in of batting. The twin package at 72 × 90 covers it with a wide strip left over; a 56 in cut off a 90 in roll (1⅝ yd) covers it with less waste. The leftover from either route pieces smaller projects: batting joins invisibly with a wide zigzag.

Packaged Batting Sizes

PackageSizeCovers quilt tops up to*
Craft36 × 45 in30 × 39 in
Crib45 × 60 in39 × 54 in
Twin72 × 90 in66 × 84 in
Full81 × 96 in75 × 90 in
Queen90 × 108 in84 × 102 in
King120 × 120 in114 × 114 in

*At 3 in overhang per side. Sizes are the common standard; brands differ by an inch or two.

Choosing a Batting Fiber

  • Cotton: flat, breathable, quilts closely, shrinks 3–5% for the crinkled look after washing. Prewash, or embrace the crinkle.
  • Polyester: loftier, lighter, no shrink, budget friendly; fibers can creep through loose weaves over years.
  • Cotton–poly blend (80/20): the longarm default: cotton’s feel with poly’s stability.
  • Wool: the loft of poly with the breathability of cotton, springs back from folding; hand-wash territory.
  • Bamboo and silk: soft drape, light warmth, the premium price shelf.

Assumptions and Defaults

  • The package match is the smallest standard size that covers your batting need in either orientation.
  • Roll yardage assumes the common 90, 96, or 124 in roll widths; the calculator picks the narrowest roll that spans your quilt’s shorter side.
  • Quilting distance, how far apart lines can run: depends on the batting’s scrim and fiber. Read the package; it overrules any chart.

Batting Questions, Answered

How much bigger than the quilt top should batting be?
Batting should be two to four inches bigger than the quilt top on every side. Quilting draws the layers in, and a longarm needs batting past the top’s edge all the way around, so the layers step up in size: top, then batting, then backing, each a little larger.
What size batting do I need for a queen quilt?
A queen quilt top of 90 × 100 in with 3 in of overhang needs 96 × 106 in of batting, which is an inch over the queen package in each direction. The king package (120 × 120 in) is the safe buy, or a 96 in cut from a 124 in roll wastes far less, and the calculator flags near-misses like this one.
Can I piece batting scraps?
Yes, you can piece batting scraps by butting the trimmed edges together with no overlap and joining them with a wide zigzag or fusible batting tape. The join disappears once the quilt is quilted, as long as you keep the pieces the same fiber and loft.
Does quilt batting shrink?
Cotton batting shrinks 3 to 5% on its first wash, which creates the soft crinkle quilters call an antique finish, whereas polyester holds its size and wool relaxes only a little. Prewashing packaged cotton batting is possible but fiddly, so most quilters quilt first and let the wash crinkle everything together.
Which side of quilt batting goes up?
On needle-punched battings, the scrim side, the denser, dimpled face, goes down toward the backing, so the needle pushes fibers into the scrim rather than pulling them up through the top. If you can’t tell the two sides apart, the difference won’t be noticeable in the finished quilt.