How do I do a stay stitch?

Staystitch by sewing a single straight line through one fabric layer, inside the seam allowance, as soon as you cut the piece. Place it about 1/8 inch inside the seamline so it won’t show, and sew each half of a neckline from shoulder to the center to keep curves from stretching during construction (see Seamwork: How to Staystitch; Tilly and the Buttons: How to Staystitch Fabric). Always follow your pattern’s instructions, your fabric care label and your machine manual, and test settings on scraps.

When to staystitch (and when to skip it)

• Use it on curved or bias edges that can stretch: necklines, some armholes, curved princess seams, bias-cut edges and often shoulders (Seamwork; Tilly and the Buttons).
• Skip it on straight edges cut on grain, and usually on knit fabrics unless your pattern specifically calls for it (Tilly and the Buttons).
• Do it early: staystitch immediately after cutting to prevent handling stretch (Seamwork).

Placement, stitch length and direction

• Placement inside the seam allowance: staystitch roughly 1/8 inch inside the seamline so it hides later. Examples: with a 5/8 inch seam allowance, stitch 1/2 inch from the raw edge (Seamwork); with a 15 mm seam allowance, stitch about 10 mm from the raw edge (Tilly and the Buttons). Always check your pattern for a specified distance.
• Stitch length: use a straight stitch. Many teachers suggest a slightly shorter stitch (around 1.5 mm) for stronger hold on curves (Seamwork), while others use a regular or slightly shorter length (about 2.0 to 2.5 mm). Test on scraps to match your fabric and pattern (Tilly and the Buttons).
• Direction: stitch both sides in the same direction to avoid distortion. For necklines, sew from each shoulder to the center front/back; for armholes (when needed), sew from shoulder to underarm (Tilly and the Buttons; Seamwork).

Step-by-step: staystitch a neckline

Prep

• Identify the seam allowance on your pattern and, if helpful, draw a light, removable guideline inside the allowance. Do not use permanent markers.
• Set a straight stitch; choose a test length on scraps of the same fabric. Thread and needle per your machine manual and the fabric; test tension on scraps.
• Lay the piece flat and support the curve so it isn’t hanging or stretching. Press only if your fabric care label allows, at the recommended setting, with a pressing cloth if needed.

Sew

• Sew within the seam allowance at the distance your pattern or testing supports. Keep the fabric relaxed and guide gently; don’t push or pull the curve as it feeds (Tilly and the Buttons).
• Sew from one shoulder to the center. Cut threads, then sew the other shoulder to center (Seamwork).

After

• Lightly press if suitable for the fabric. The staystitch remains hidden in the allowance and helps preserve the shape while you attach facings, bindings or collars (Tilly and the Buttons).
• If the edge still wants to grow, add narrow stay tape or lightweight interfacing on the wrong side before continuing (Tilly and the Buttons). For a refresher on fusing technique, see Attach fusible interfacing properly: clear steps.

Common mistakes and fast fixes

• Visible staystitching after seaming: first check that the permanent seam follows the pattern. Do not move that seam merely to hide a stray staystitch. Once the permanent seam supports the edge, carefully remove only the visible staystitches if necessary without cutting the fabric or stretching the curve (Tilly and the Buttons).
• Ripples or a wavy curve: avoid stretching as you sew, and follow directional stitching. Stabilize with stay tape or lightweight interfacing if the fabric is especially unstable (Tilly and the Buttons).
• Waiting too long: staystitch immediately after cutting; later stitching won’t reverse stretching from handling (Seamwork).

How staystitching differs from other stitches

• Basting: temporary long stitches to hold layers together; removed later. Staystitching is permanent and sewn on a single layer inside the allowance.
• Understitching: stitches a facing to the seam allowance to keep edges rolled in; done after seaming, near the edge.
• Topstitching: visible stitching on the outside for strength or decoration; not inside the allowance.

Good to know

• Neckline and armhole distances vary with seam allowance. If you’re unsure, review your pattern and see What is the standard seam allowance for sewing?
• Knit fabrics: unless your pattern says otherwise, don’t staystitch knits; stabilize as directed by the pattern (Tilly and the Buttons).