How to make a stroller seat liner

1. Materials & tools

Materials (full-recline stroller)

• Main fabric (six-layer gauze, toweling or printed cotton) — about 110 cm wide × 90 cm (44 × 35 in)
• Backing fabric (muslin or light cotton) — the same amount
• Lightweight batting — the same amount, for a little padding
• Eyelet pliers, or a buttonhole foot, for the harness slots

Tools

• Sewing machine (or needle and thread)
• Fabric marker or pencil
• Ruler and scissors
• Iron
• Pins or clips

2. Make the pattern (auto-generated in Katagami)

With the Katagami pattern tool, you just enter the finished size and it drafts a seam-allowance-included pattern, tiled to print at actual size on Letter or A4.

1. Open the tool
   Open the pattern tool and choose “Baby” → “Stroller seat liner” from the tabs at the top.
2. Enter the size
   Enter the backrest width and height, seat width and depth, and the corner radius. Presets cover full-recline, lightweight and car seats.
3. Set the seam allowance
   Use the slider at the bottom (beginners: 1.0–1.5 cm / about 3/8–5/8 in).
4. Print
   Press “Print (actual size)”, then in the print dialog set Scale = 100% and turn “Fit to page” OFF. Check the 50 mm calibration box on the first guide sheet with a ruler.

3. Cutting the fabric

1. Measure your stroller
   Measure the backrest width and height and the seat width and depth. Also measure where the harness straps come through, from the edge of the seat.
2. Trace the pattern
   Trace the body. The marked points are suggested harness slot positions.
3. Cut
   Cut the main and backing fabric, and the batting 1 cm smaller all round so the seam allowance is not bulky.
4. Check the slot positions
   The pattern marks are typical. If your measurements differ, mark your own instead.

4. Sewing

4-1. Layer and sew

1. Stack backing right side up, main fabric right side down, then batting on top.
2. Sew all the way around, leaving a 15 cm (6 in) gap.
3. Clip the outer corner curves, and clip into the inward corners where the back meets the seat — skip that and it will pull when turned.

4-2. Turn and topstitch

1. Turn through the gap and ease the corners out.
2. Press the edges, using a pressing cloth and a light hand so the batting is not flattened.
3. Topstitch 1 cm (⅜ in) from the edge all the way around, closing the gap.

4-3. Make the harness slots

1. Mark your measured positions: two for the shoulder straps and one for the crotch strap.
2. Either set eyelets or work large buttonholes, about 5 mm wider than the harness webbing.
3. Hold it in the stroller and check the positions before you cut anything. This step cannot be undone.
4. Stitch a rectangle around each slot so it cannot spread under load.

4-4. Tack the layers

1. Tack through all layers at a few points, two or three stitches every 20 cm (8 in), so the batting cannot shift.

✏️ Do not trust the pattern's slot marks. Shoulder strap spacing and crotch strap position vary enormously between models. Measure your own, mark them, then hold the liner in place and check again before you cut.

5. Tips & variations

• Gauze against the skin: the side the baby lies on should be absorbent. Gauze or toweling, not laminate.
• Make two: this gets washed constantly.
• Or skip the slots: for short trips you can simply lay it in place without threading the harness through at all.