Batting Size Calculator

How the batting math works

Like backing, batting should hang past the quilt top so it can shift slightly while you quilt without leaving a corner short. Four inches a side is standard for longarm work; two is fine on a domestic machine.

A worked example: batting for a 60″ × 72″ throw

With 4″ of overhang on every side, compared against a 96″ roll — the calculator's defaults:

This is the case where the package and the roll are genuinely close, so buy whichever is cheaper per quilt — but note the leftovers differ. The Twin package leaves you an unusable 4″ strip; two yards off a 96″ roll leaves a 16″ × 96″ piece that is big enough for a table runner or a pieced batting scrap.

Package vs. by the yard

Packaged batting comes in bed sizes (Craft, Crib, Twin, Full, Queen, King) and you pay for the whole package whatever your quilt measures. Off a roll you buy only the length you need, which is nearly always cheaper for odd sizes, and rolls come in wider widths — 96″ and 120″ — so a wide quilt may need no piecing at all. The full size table is in standard batting sizes.

Loft and fibre change the answer

Cotton batting shrinks 3-5% on first wash, which is what gives an antique crinkle; if you want that, the overhang matters more, not less. Polyester does not shrink and has more loft. Wool is light and springy and shows quilting sharply. Bamboo and blends sit in between. None of this changes the size arithmetic, but it changes what you buy — compare batting types and the loft guide before ordering.

Common mistakes

Buying batting to the quilt's exact size. There is no way to keep the edges square without overhang. Ignoring the quilting density the batting requires. Every batting states a maximum distance between lines of quilting — commonly 4″ to 10″ — and exceeding it lets the batting shift and bunch inside the quilt after washing. Assuming a package is the size on the label. Packaged batting is often an inch or two under the stated size once unfolded; measure before you cut.

Common questions

Can I piece batting from scraps?

Yes. Butt the edges together — do not overlap — and join them with a wide zigzag or a purpose-made fusible batting tape. A pieced batting is invisible once quilted.

Do I really need 4 inches all round?

On a longarm, yes; the quilt is loaded on rollers and the edges need something to grip. Quilting on a domestic machine, 2″ is usually enough.

Should I prewash batting?

Generally no — most cotton batting is meant to shrink slightly with the quilt, which is the crinkled look. Check the manufacturer's instructions, which vary.