How to Calculate Quilt Batting: A Complete Guide

Quick answer: how to calculate batting

Batting size equals top width plus 2 times overhang, by top length plus 2 times overhang. Then check both orientations against roll width. Orientation A: strips equal batting width divided by roll width, rounded up, total length equal strips times batting length. Orientation B, rotated 90 degrees: strips equal batting length divided by roll width, rounded up, total length equal strips times batting width. Choose the smaller total length. Yardage to buy is total length divided by 36, rounded up to the nearest 1/8 yard. This calculator has no seam field, because batting pieces are butted, not seamed with an allowance, and both orientations are always checked.

Example: a twin top 68 by 88 inches, overhang 4 inches, roll width 90 inches. Batting size is 76 by 96 inches. Orientation A gives 1 strip, 96 inches, buy 2.75 yards. Orientation B gives 2 strips, 152 inches, buy 4.25 yards. Chosen is orientation A, 2.75 yards, and the smallest common precut that fits is Full 81 by 96 inches.

If you only need a number, use the Batting Calculator. If you want to understand why both orientations must be checked, and what precut fits, read on.

What batting is

Batting is the middle layer of the quilt sandwich, between the quilt top and the backing. It gives a quilt its warmth, its thickness, and its drape. Without batting, a quilt top and backing sewn together would be flat, like a sheet, not a quilt.

Batting is not fabric in the usual sense. It is a sheet of fibres, sold on a roll, or cut to a pre-cut size, in a package. It has no print, no grain in the same way as quilting cotton, and it is usually non-directional, which matters for the calculation below.

Batting compared with backing

Batting	Backing
Middle layer of the quilt sandwich	Bottom layer of the quilt sandwich
Usually cut to the same size as backing, or a little smaller	Usually cut larger than the top, with overhang for quilting
Joined edge to edge, with a butt join, when it needs to be pieced	Joined with a fabric seam allowance, when it needs to be pieced
Loft and fibre type change thickness and drape, not yardage	Fabric width and panel count change yardage

Step by step: how to calculate batting

Step 1: Get batting size needed

Batting width equals top width plus 2 times overhang. Batting length equals top length plus 2 times overhang. Overhang is added on each side, so it is counted twice. Batting is usually cut to the same size as backing, or a little smaller. Enter your desired batting overhang, not necessarily your backing overhang, if they differ.

Step 2: Work out orientation A, as entered

Orientation A keeps batting width across the roll width. Strips needed in orientation A equals batting width divided by roll width, rounded up to the next whole strip. Total length in orientation A equals strips needed times batting length.

Step 3: Work out orientation B, rotated 90 degrees

Orientation B rotates batting by 90 degrees, so batting length runs across the roll width. Strips needed in orientation B equals batting length divided by roll width, rounded up to the next whole strip. Total length in orientation B equals strips needed times batting width.

Step 4: Choose the orientation that uses less length

Choose the orientation with the smaller total length. If both orientations use the same total length, choose orientation A, as entered. Batting is usually non-directional, so rotating it to save yardage is usually fine. If your batting has a directional loft or a scrim side, follow the batting package directions instead of rotating.

Step 5: Work out yardage

Exact yardage equals total length chosen divided by 36 in inch mode. Yardage to buy is exact yardage rounded up to the nearest 1/8 yard. In centimetre mode, metres to buy are rounded up to the nearest 0.1 metre.

Step 6: Check a pre-cut, for comparison

Check the smallest common pre-cut size that fits batting size needed, from Crib 45 by 60 inches, Twin 72 by 90 inches, Full 81 by 96 inches, Queen 90 by 108 inches, and King 120 by 120 inches. Pre-cut sizes vary by brand, so check the package size before buying. A pre-cut may be easier than cutting from a roll, but it may cost more per yard than roll yardage.

Worked example: a twin quilt

Take a twin top 68 by 88 inches, overhang 4 inches on each side, batting roll width 90 inches.

Batting size needed: width 68 plus 8 equals 76 inches. Length 88 plus 8 equals 96 inches.

Orientation A, as entered: strips needed equals 76 divided by 90, rounded up, equals 1 strip. Total length equals 1 times 96, equals 96 inches. Exact yardage: 96 divided by 36 equals 2.67 yards. Yardage to buy: 2.75 yards.

Orientation B, rotated 90 degrees: strips needed equals 96 divided by 90, rounded up, equals 2 strips. Total length equals 2 times 76, equals 152 inches. Exact yardage: 152 divided by 36 equals 4.22 yards. Yardage to buy: 4.25 yards.

Chosen orientation: orientation A, as entered, because total length 96 inches is less than total length 152 inches. Yardage to buy: 2.75 yards. In this example, rotating does not save yardage, it costs more, because rotating creates a second strip. That is why both orientations must be checked, not assumed.

Pre-cut check: batting size 76 by 96 inches fits in Full 81 by 96 inches, which is the smallest common pre-cut that fits. Check the package size before buying, because pre-cut sizes vary by brand.

Precut table, our own computed table

This table lists the precut sizes the calculator checks, and the largest top each one fits at 4 inches overhang per side, computed as precut size minus 8 inches on each side. It is computed from the calculator's precut list, not copied from another site. The calculator's list has no Craft or Throw precut, so those sizes are not shown as calculator results here.

Precut	Largest top it fits, at 4 in overhang
Crib 45 by 60 in	37 by 52 in
Twin 72 by 90 in	64 by 82 in
Full 81 by 96 in	73 by 88 in
Queen 90 by 108 in	82 by 100 in
King 120 by 120 in	112 by 112 in

If no precut fits, buy from a roll, and check both orientations before cutting, because a rotated roll can need fewer strips, or more, as the twin example shows.

How to make sure your result is correct

• Batting size check. Batting width must equal top width plus 2 times overhang, and batting length must equal top length plus 2 times overhang.
• Orientation check. Both orientations must be computed. Rotating does not always save yardage, it can cost more, as the twin example shows.
• Strip check. Strips must be rounded up to a whole strip. A fraction of a strip cannot be bought or cut.
• Buy versus exact check. Buy yardage must never be below exact yardage. If it is, you rounded the wrong way.
• Precut check. A precut fits only when batting width fits in precut width AND batting length fits in precut length. One side fitting is not enough.
• Overhang check. Overhang is for shifting and clamping during quilting, and for trimming after quilting, not extra batting to keep in the finished quilt. Ask a longarmer for their required overhang, because 4 inches per side is a starting point, not a universal rule.

How to join batting, in brief

1. Cut batting pieces to the sizes from the calculation, and lay them flat, edge to edge, with no overlap and no gap.
2. Join the pieces edge to edge. Common methods are a wide zigzag stitch across the join, a hand whip stitch, or fusible batting tape, following the tape package directions. Do not overlap batting pieces, because an overlap creates a thick ridge that shows after quilting.
3. Press or steam the join flat, if the batting package allows it, and check that the joined batting lies flat before basting.
4. Check batting size against backing size before basting. Batting should be the size you planned, not smaller, or the edges of the quilt sandwich will be uneven.

This is a summary, not a full batting joining tutorial. If you have never joined batting, practice on scraps first, and check that the join lies flat after quilting a sample, before joining batting for a finished quilt.

Choosing batting type and loft

Batting type and loft do not change yardage, so they are not inputs in the calculator. They do change how a quilt feels and how it must be quilted. Cotton batting gives a flat, traditional drape. Polyester batting gives more loft and puff. Wool batting gives warmth with less weight. Blends try to balance these qualities. Loft is thickness, from low loft, which is flat, to high loft, which is puffy.

Quilting distance also varies by batting type. Some battings allow quilting lines far apart, others need quilting lines closer together, or the batting can bunch or shift in washing. Check the batting package for its recommended quilting distance, and do not guess it, because it is specific to the batting you bought.

Common mistakes with batting

• Cutting batting to top size, with no overhang. Batting needs overhang for quilting and trimming, just like backing. Cut batting larger than the top, not the same size as the top.
• Overlapping batting pieces when joining. An overlap creates a thick ridge. Join batting edge to edge, with no overlap and no gap.
• Assuming rotation always saves yardage. Rotation sometimes saves yardage, and sometimes costs more, as in the twin example above. Check both orientations, every time.
• Rounding yardage down. Rounding down gives batting that is too short. Always round yardage up.
• Ignoring quilting distance. Quilting distance varies by batting type. Check the package, and quilt within its recommended distance, or batting can shift in washing.

Frequently asked questions

Related guides and calculators

Next, read How to Calculate Quilt Size for the top size that batting size starts from, and use the Batting Calculator for your own numbers. For fabric for the top itself, see How to Calculate Quilt Fabric.