How to Sew Flannel Diaper Liners from Printed Fabric

By Green Mountain Diapers | Published: 2026-11-03

Category: Guide pratiche

Turn soft printed flannel into reusable diaper liners with a simple sew-and-wash process. Get the pattern, stitching checkpoints, and care steps that keep liners flat and useful.

Quick answer

Cut two squares of pre-washed printed flannel, sew them right sides together with a small turning gap, clip the corners, turn, and topstitch. Wash the finished liners once before first use and line dry or tumble low.

Why printed flannel works as a liner

Flannel is soft against skin and holds a liner in place without bulk, which makes it a practical choice for a reusable diaper liner. Printed cotton flannel also lets you use up cute fabric remnants, so you can match liners to a diaper stash or designate different prints for different children.

The trade-off is shrinkage and raveling. Cotton flannel can shrink noticeably after the first wash, so pre-wash and dry the fabric before cutting. Finished edges on the fabric help, but cut edges still need to be enclosed or zigzagged so they do not fray in the wash.

Choosing and preparing flannel fabric for diapers

Use 100% cotton flannel for breathability and easy washing. Avoid fabric with heavy surface coatings or metallic prints if you are unsure how they will wear, and choose prints you can identify quickly when sorting laundry. A 30 x 30 inch piece is enough for several small liners, but plan around shrinkage: the usable size after washing is smaller than the cut size.

Pre-wash the fabric in warm water and dry it before cutting. This removes sizing and pre-shrinks the flannel so your finished liners keep their shape. If you skip this step, a liner cut to fit may shrink after the first diaper wash and curl at the edges.

Reusable diaper liner pattern and sizing

A simple two-layer square or rectangle is enough for most liners. For a newborn, start around 4 x 8 inches; for an older baby, try 5 x 10 inches. These are starting points, not fixed rules: check the liner against the diaper you plan to use it with, and remember that a two-layer liner will be slightly smaller after sewing and washing.

If you want a stay-dry liner, use a single layer of flannel on top and a stay-dry fabric underneath, but only if you know that fabric is suitable for diapers. For a purely flannel liner, two layers give a bit more substance without much bulk.

Step-by-step: sew and care for flannel liners

Pre-wash and dry the flannel: Wash the fabric in warm water with a small amount of mild detergent, then tumble dry low or line dry. This pre-shrinks the cotton flannel before you cut. Measure the fabric after drying; use the shrunken size to plan how many liners you can cut.
Cut two matching pieces per liner: Fold the pre-washed flannel and cut two rectangles of the same size for each liner. Keep the rotary cutter or scissors sharp so the edges stay clean. Cut one test liner first and check it against your diaper before cutting the rest.
Sew right sides together with a turning gap: Place the two pieces right sides together and sew around the edge with a 1/4-inch seam allowance, leaving a 2-inch gap on one side for turning. Backstitch at the start and end of the gap. Do not sew the gap closed; you need it to turn the liner right side out.
Clip corners and turn: Clip the seam allowance at the corners without cutting through the stitching. Turn the liner right side out through the gap and push the corners out gently with a blunt tool. Clipping too close to the seam can create a hole; stop just short of the stitching.
Topstitch the edge and close the gap: Press the liner flat, then topstitch 1/8 inch from the edge all the way around, folding the gap edges inward as you sew. This closes the gap and keeps the layers from shifting. A slightly longer stitch length helps the flannel feed smoothly without puckering.
Wash before first use and care for the liners: Wash the finished liners once in warm water with diaper-safe detergent and dry them fully. For routine care, wash with your diaper load, avoid fabric softener, and line dry or tumble low. Fabric softener can coat the fibers and reduce absorbency; skip it to keep the flannel working well.

Fabric facts for this project

Flannel Printed Fabric: 100% cotton printed flannel with finished edges, about 30 x 30 inches before shrinkage and roughly 28 x 28.5 inches after washing. Plan your liner count from the post-wash size, not the cut size, so the pieces you cut still fit after the first wash.
Flannel Printed Fabric