How to make a mask case

1. Materials & tools

Materials (one case)

• Main fabric (laminated cotton, oxford or cotton) — about 30 × 30 cm (12 × 12 in)
• Lining fabric — the same amount
• Snap fastener or hook-and-loop — 1 set
• Lightweight interfacing if the fabric is thin

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 “Accessories” → “Mask case” from the tabs at the top.
2. Enter the size
   Enter the finished width, height and flap depth. Presets cover child, standard and large.
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. Trace the pattern
   Trace the body and mark the fold line.
2. Cut
   Cut one main and one lining. Use clips rather than pins on laminated fabric.
3. Apply interfacing
   On thin fabric, fuse interfacing to the main piece so the case holds its shape.

4. Sewing

4-1. Sew the layers together

1. Place main and lining right sides together and sew around, leaving an 8 cm (3 in) gap.
2. Trim the corners diagonally so they turn out sharp.

4-2. Turn and topstitch

1. Turn through the gap, ease the corners out and press.
2. Topstitch 3–5 mm from the edge all the way around, closing the gap.
3. You now have a two-sided rectangle.

4-3. Fold and stitch the sides

1. Fold up from the bottom at the marked line, leaving the flap standing above.
2. Stitch both sides 2–3 mm from the edge. This stitching shows, so match your thread to the main fabric.
3. Backstitch at the start and end of each side seam.

4-4. Add the fastening

1. Close the flap and mark where the fastening lands.
2. Fit a snap or hook-and-loop 2–3 mm outside your mark to allow for the thickness of a mask inside.

✏️ For an internal divider, sew a slightly smaller piece to the lining on three sides at step 4-3, before folding — and hem its top edge first. Neither can be done once the case is assembled.

5. Tips & variations

• Laminated lining: a wipe-clean inside means a used mask does not contaminate the case.
• Keep it slim: heavy interfacing makes it too bulky for a pocket. Lightweight is right.
• Other uses: at other sizes this is a passbook case or a ticket wallet.