The Basic Method for Attaching a Dress Strap

A dress strap is sewn on by pinning it to the dress body, then stitching it down with a needle and thread or a sewing machine. The strap sits between two layers of fabric — the dress exterior and the dress lining or facing — so the raw edges stay hidden inside. Most straps are sewn on before the dress is fully assembled, but you can also attach one to a finished dress by hand-stitching it to the seam allowance.

The method depends on whether you are working with a lined dress, an unlined dress, or a dress that is already complete. Each approach uses the same basic stitch but requires you to position the strap differently. The most common scenario — sewing a strap into a seam during construction — takes about 15 to 20 minutes per strap once you have pinned it in place.

Key Takeaways

  • A strap is sandwiched between the dress exterior and the facing or lining, with raw edges hidden inside, so it must be sewn before the dress is fully assembled in most cases.
  • Pin the strap to the dress body first, matching the placement marks you made on your pattern, then stitch it down with a straight stitch using a 5/8-inch seam allowance.
  • Press the seam open or to one side after stitching to reduce bulk and help the strap sit flat against the dress.
  • If you are adding a strap to a finished dress, hand-stitch it to the existing seam allowance using a ladder stitch or whip stitch so the stitches do not show on the outside.

Preparing the Strap and Marking Placement

Before you sew, cut your strap to the correct length and width. Most dress straps are 1.5 to 2 inches wide when finished, which means you cut them 3 to 4 inches wide to account for seam allowances on both long edges. The length depends on your pattern — measure from the front bodice to the back bodice along the line where the strap will sit, then add 1.25 inches for seam allowances at each end.

Mark the placement on your dress pieces using tailor's chalk or a fabric pencil. Your pattern will show you exactly where the strap begins and ends on the front and back bodice. Make a small mark at each end of the strap placement line on both the dress exterior and the facing or lining piece. These marks keep the strap from shifting as you sew.

If your strap is made from two pieces of fabric sewn together and turned right-side out (the most common method), press it flat before you pin it to the dress. The strap should be crisp and even, with the seam running down the center of one long edge.

Pinning and Stitching the Strap to the Dress

Place the dress exterior and the facing or lining piece right sides together, as if you were about to sew the armhole or neckline seam. Position the strap between these two layers with the raw edges of the strap aligned with the raw edges of the dress pieces. The finished edge of the strap (the edge that will show on the outside of the dress) should point toward the interior of the dress at this stage.

Pin the strap in place, matching the placement marks you made earlier. Use pins perpendicular to the seam line, spacing them about 2 inches apart. Check that the strap is not twisted and that both ends are aligned with your marks before you begin stitching.

Sew the strap down using a straight stitch with a 5/8-inch seam allowance. Backstitch at the beginning and end to lock the thread. Sew slowly and keep the edge of the presser foot aligned with the raw edges of the strap and dress pieces. After stitching, remove the pins and press the seam open or to one side, depending on your pattern instructions. This reduces bulk and helps the strap lie flat.

Finishing the Seam and Turning the Dress Right-Side Out

Once you have stitched the strap to both the dress exterior and the facing, you will sew the facing to the dress along the same seam line. This sandwiches the strap between the two layers. When you turn the dress right-side out, the strap will be permanently anchored in place with no raw edges visible.

Trim the seam allowance to 1/4 inch if your fabric is thick or if your pattern calls for it. Clip into the seam allowance at curves or corners to help the fabric turn smoothly. Grade the seam allowance — trim the facing seam allowance slightly narrower than the dress seam allowance — so the layers do not create a visible ridge on the outside of the dress.

Turn the dress right-side out through an opening left in the facing or lining. Push the strap out gently with your fingers or a point turner so it sits smoothly against the dress. Press the seam from the inside of the dress, using a pressing cloth if your fabric is delicate.

Adding a Strap to a Finished Dress by Hand

If your dress is already complete and you need to add or replace a strap, you can hand-stitch it to the existing seam allowance. This method works best if the seam allowance is at least 1 inch wide and if the strap will not bear much weight.

Pin the strap to the dress, positioning it so that the raw edges of the strap sit inside the seam allowance and the finished edges of the strap are visible on the outside. Use a ladder stitch (also called an invisible stitch) to close the opening, stitching through the fold of the strap and the fold of the dress seam allowance. This stitch is nearly invisible from the outside because the thread runs inside the fold of the fabric.

Alternatively, use a whip stitch if the strap edges are folded under. Bring the needle up through the fold of the dress seam allowance, then down through the fold of the strap, moving forward about 1/8 inch with each stitch. Keep the stitches small and tight so they do not slip.

Reinforcing the Strap at Stress Points

The ends of the strap — where it meets the dress bodice — bear the most stress, especially if the dress is worn frequently or if the strap supports weight. Reinforce these points by stitching a small rectangle or box at each end of the strap, stitching through all layers of fabric.

After you have sewn the strap in place and pressed the seam, stitch a rectangle about 1 inch long and 1/2 inch wide at each end of the strap, using a straight stitch. Some sewers stitch an X inside the rectangle for extra strength. This stitching is visible on the inside of the dress but not on the outside, and it prevents the strap from tearing away from the bodice.

If the dress will be worn under stress — a heavy fabric, a large bust size, or frequent wear — consider stitching a second line of stitching 1/4 inch away from the first seam line, running parallel to it. This is called a stitch-in-the-ditch and is nearly invisible from the outside because it sits in the crease of the seam.

Common Mistakes and How to Avoid Them

The most common mistake is sewing the strap on upside down, so the raw edges show on the outside of the dress. Check your placement before you pin: the finished edge of the strap should point inward, toward the facing or lining, not outward toward the exterior of the dress.

Another mistake is not pinning the strap straight, so it twists or angles as you sew. Take time to pin it carefully, checking that both ends are aligned with your placement marks and that the strap does not spiral or bunch. A twisted strap will look crooked on the finished dress and may not sit comfortably on your shoulder.

Pressing the seam too hard or with too much heat can distort the strap, especially if it is made from a stretchy or delicate fabric. Use a pressing cloth and press gently, lifting the iron rather than sliding it along the seam. Let the fabric cool before you move it.

Frequently Asked Questions

Can I sew a strap on by machine if the dress is already finished?

Yes, but hand-stitching is easier because you can control the stitch placement more precisely and avoid stitching through layers that are hard to reach with a presser foot. If you use a machine, use a zipper foot or a narrow presser foot so you can stitch close to the edge of the strap without catching the dress fabric underneath.

What stitch should I use to sew the strap on?

A straight stitch is standard and strongest. Some sewers use a narrow zigzag stitch to prevent fraying, but this is not necessary if you are sandwiching the strap between two layers of fabric. If you are hand-stitching, use a ladder stitch or whip stitch so the stitches do not show on the outside.

How wide should the seam allowance be when I sew the strap?

Use a 5/8-inch seam allowance to match the rest of the dress. If your pattern specifies a different seam allowance, follow that instead. After stitching, you can trim the seam allowance to 1/4 inch to reduce bulk, especially if your fabric is thick.

What if the strap is too long or too short after I sew it on?

If the strap is too long, you can trim it before you sew it on. If it is too short after sewing, you can add a small piece of fabric to extend it, stitching the extension to the strap before you attach it to the dress. If the strap is already sewn on, you can remove the stitches, adjust the length, and re-sew it.

Do I need to use a facing, or can I sew the strap directly to the dress?

A facing or lining hides the raw edges of the strap, which is why it is standard. If your dress has no facing or lining, you can sew the strap on and then fold the raw edges of the strap and dress seam allowance under and hand-stitch them closed, but this creates more bulk and is less durable than using a facing.