Swayback adjustment

If fabric pools in horizontal folds above your bottom at the back, a swayback adjustment removes a wedge of length from the back pattern at centre back, tapering to nothing at the side.

Pinny's tip
Pin out the fold on a toile to measure exactly how much to remove.

What you'll need

• Toile: to measure the fold.
• Back pattern piece: traced copy.
• Ruler: to redraw the centre back.

Step by step

1. On the toile, pin out the horizontal fold at the centre back and measure the depth.
2. On the pattern, draw a line from centre back to side seam at that level.
3. Fold out a wedge the size of the fold at centre back, tapering to zero at the side.
4. Redraw the centre back as a straight or gently curved line.
5. If the piece is cut on the fold, see the video on adjusting with no centre back seam, or add a seam.

Common mistakes

• Taking out width at the side. The wedge tapers to nothing there.
• Guessing the amount. Measure on a toile.
• Forgetting a fold line. Pieces cut on the fold need another approach.

Watch it done

• Learn to Sew – How to Sew a Sway Back Adjustment on YouTube. Opens on YouTube; the video belongs to its creator.
• DIY Swayback Adjustment by Rivet Patterns on YouTube. Opens on YouTube; the video belongs to its creator.
• How to do a Sway Back Adjustment with No Center Back Seam by J Stern Designs on YouTube. Opens on YouTube; the video belongs to its creator.

Sources

All checked November 1, 2026. We read these; we did not test the products ourselves.

1. Tilly and the Buttons: Fitting the Rosa Shirt and Dress
2. By Hand London: Jenna Dress Sewalong - Swayback adjustment
3. YouTube: DIY Swayback Adjustment (Rivet Patterns)
4. YouTube: How to do a Sway Back Adjustment with No Center Back Seam (J Stern Designs)