Quilt Backing Fabric: How Much to Buy and How to Piece It

By Colibri Sewing | Sewing & Quilting Supplies | Published: 2026-10-16

Category: How-to Guides

Learn how to calculate quilt backing yardage, choose between 44-inch and 108-inch wide fabric, and piece a backing with a strong seam.

Quick answer

For a quilt up to 40 inches wide, buy one length of 44-inch fabric equal to the quilt length plus 8 inches. For wider quilts, either piece two or more lengths of 44-inch fabric or buy 108-inch wide backing fabric cut to your quilt length plus 8 inches. Always add extra for longarm quilting and shrinkage.

Measure your quilt top before you buy

Lay the quilt top flat and measure the width and length at the widest and longest points. Do not rely on the pattern's finished size; piecing and quilting can change dimensions. Write down both numbers and add 4 inches to each side for quilting take-up and shrinkage. For example, a 60x80 quilt top needs a backing at least 68x88 inches.

Choose between 44-inch and 108-inch wide fabric

Standard quilting cotton is 44/45 inches wide, so a single width works only for quilts up to about 40 inches wide after adding margin. Wider quilts require piecing two or more lengths, which adds a seam. If you dislike piecing or want a seamless back, 108-inch wide backing fabric eliminates the seam but comes in fewer prints. For a 60-inch wide quilt, 108-inch backing gives you plenty of width with no piecing.

Calculate yardage for pieced backing

For a quilt wider than 40 inches, divide the needed backing width by 40 (the usable width of 44-inch fabric after selvedges). Round up to the next whole number. That is how many lengths you need. Multiply that number by the needed backing length in inches, then divide by 36 to get yards. For a 68x88 backing, 68 divided by 40 is 1.7, so you need 2 lengths. 2 times 88 is 176 inches, which is 4.89 yards. Buy 5 yards to be safe.

Piece the backing with a strong seam

Trim selvedges before seaming; they are tightly woven and can cause puckering. Place right sides together and sew a 1/2-inch seam, then press the seam open. A 1/2-inch seam is stronger than a 1/4-inch seam for backing. If you want a horizontal seam, rotate one length 180 degrees before sewing so the seam runs across the width. Horizontal seams are less noticeable on longarm frames because the roller advances over the seam.

Decide horizontal vs vertical backing seam

A horizontal seam runs across the quilt width; a vertical seam runs from top to bottom. Horizontal seams are often preferred for longarm quilting because the seam is parallel to the rollers and less likely to create bulk. Vertical seams work well for domestic machine quilting where you roll the quilt from the sides. Either way, press the seam open and trim any stray threads.

Step-by-step: backing from measurement to basting

Measure the quilt top: Measure width and length at the widest and longest points. Add 4 inches to each side for margin. Checkpoint: your backing must be at least 4 inches larger than the quilt top on all sides.
Calculate yardage for 44-inch fabric: Divide needed width by 40. Round up to get the number of lengths. Multiply lengths by needed length, then divide by 36. Round up to the nearest 1/2 yard. Common mistake: forgetting to round up the number of lengths, which leaves you short.
Calculate yardage for 108-inch wide backing: Buy one length equal to the quilt length plus 8 inches. No piecing needed for quilts up to 100 inches wide. Checkpoint: 108-inch backing is sold by the yard; order the exact length you need.
Piece the backing if needed: Trim selvedges, sew lengths with a 1/2-inch seam, and press the seam open. For a horizontal seam, rotate one length 180 degrees before sewing. Common mistake: sewing with selvedges intact, which causes puckers.
Press and square the backing: Press the seam open and square the backing edges so it lies flat. Trim any stray threads. Checkpoint: the backing should be flat with no ripples before basting.
Baste or load the quilt: Baste with your preferred method, or load onto a longarm frame. Keep the backing taut but not stretched. Next step: quilt as desired, then bind.

Fabric facts that affect backing

Tula Pink Neon True Colors Tented Stripes - Spirit 1/2 yd: Tula Pink Neon True Colors Tented Stripes - Spirit is 100% quilting-weight cotton, 44/45 inches wide, sold by the 1/2 yard. At 44/45 inches wide, this fabric is best for small quilts or as one of several lengths when piecing a larger backing.
Baked with Love 1/2 Yard – Tradition Schoolhouse: Baked with Love 1/2 Yard – Tradition Schoolhouse is a Lori Holt for Riley Blake Designs print, sold by the half yard, cut 18 x 44 inches. The half-yard cut means you can buy exactly the number of lengths you calculate without waste, but you will need to piece for quilts wider than 40 inches.
Whispering Pines 1/2 Yard – Main Green: Whispering Pines 1/2 Yard – Main Green is a Riley Blake Designs print, sold by the half yard, cut 18 x 44 inches. This nature-inspired print works as a backing when you want a coordinated look, but its 44-inch width requires piecing for wide quilts.