A narrow shoulder adjustment shortens the shoulder seam of a bodice so the armhole seam sits on the tip of your shoulder bone instead of sliding down your arm. You move the shoulder point inward by the difference between your shoulder width and the pattern's, usually 1 to 2 cm (3/8 to 3/4 in) per side, by pivoting the upper armhole in rather than redrawing it, so the armhole keeps its length and the sleeve still fits. Narrow shoulders are the most common fit issue on commercial patterns, because standard size charts widen the shoulders as the bust grows, and real bodies often do not.

How do you spot that a pattern's shoulders are too wide?

With the toile on and your arms relaxed, feel for the tip of your shoulder bone, the bony point where the arm begins. Then look at where the armhole seam sits:

  • The seam sits past the bone, on the upper arm, by a centimeter or more.
  • The sleeve cap collapses into a soft fold just below the shoulder seam, because there is no shoulder to hold it up.
  • Diagonal drag lines from the shoulder point toward the bust or the shoulder blade, pointing inward, as the extra width folds over the arm.
  • The shoulder seam looks long and the whole top seems to droop at the corners, even though the bust and waist fit.
  • On a sleeveless top, the armhole gapes at the top of the arm.

A dropped shoulder is a design choice on some garments, oversized tees and sweatshirts for example, and should be left alone. The adjustment is for garments drafted with a set-in sleeve that is meant to start at the shoulder: blouses, shirts, dresses, jackets and fitted T-shirts.

Narrow shoulders and sloping shoulders are often confused. A long shoulder seam droops over the arm; a sloping shoulder leaves a gap under the seam near the armhole with folds that start at the neck. Shorten the seam first, make a new toile, then look at the slope.

How much do you take off?

Measure your shoulder width across the back, from the tip of one shoulder bone to the other, with a tape held flat over the shoulder blades. Have someone else do it if you can; the post on measuring shoulder width explains how to find the bone and why measuring alone usually overestimates it.

On the pattern, measure the shoulder seam on the stitching line from the neck point to the shoulder point on the back piece, double it, and add the back neck width (twice the distance from the center back to the neck point, measured straight across). That is the pattern's shoulder-to-shoulder width. Compare it with your measurement. The difference, divided by two, is the amount to remove at each shoulder point.

For example, a pattern with a 12.5 cm (4 7/8 in) shoulder seam and a 15.5 cm (6 1/8 in) back neck measures 40.5 cm across. A 37.5 cm (14 3/4 in) shoulder width needs 3 cm less, so 1.5 cm (5/8 in) off each side.

On a toile, the quick method is to pin a vertical tuck through the middle of the shoulder seam, down into the armhole, until the seam ends on your bone. The width of the tuck is your amount.

How do you do a narrow shoulder adjustment, step by step?

The pivot method is the standard one. It keeps the armhole curve the same length, so the sleeve goes in without change.

  1. Mark the new shoulder point. On the front bodice, measure inward from the shoulder point along the shoulder seam by your amount, say 1.5 cm (5/8 in). Mark it.
  2. Draw an L-shaped cut line. Draw a line from the middle of the shoulder seam straight down about 8 cm (3 in), then across to the armhole at the level where the armhole curve starts to turn under toward the underarm, roughly a third of the way down. The box you have drawn contains the shoulder point and the upper part of the armhole.
  3. Cut the L, leaving a paper hinge at the armhole end of the horizontal line. The box is now a flap attached to the rest of the pattern at that hinge.
  4. Pivot the flap inward so the shoulder point moves 1.5 cm toward the neck. The cut at the shoulder overlaps; the hinge holds the lower armhole in place. Tape it.
  5. Redraw the shoulder seam as a straight line from the neck point to the new shoulder point. The seam is now 1.5 cm shorter and keeps its original slope.
  6. Smooth the armhole. There may be a tiny step where the flap meets the lower curve. Blend it with a curve ruler. The total armhole length changes by a millimeter or two at most.
  7. Repeat on the back with the same amount, aligning the L the same way.
  8. Walk the sleeve. Measure the front and back armhole on the stitching lines and compare with the sleeve cap. The sleeve cap ease should be as the designer intended; if the armhole has shrunk by more than 5 mm (1/4 in), you have cut too low into the armhole and should redo the L with the horizontal line higher.

For adjustments of 1 cm (3/8 in) or less, you can skip the slash and redraw instead: mark the new shoulder point, then draw a new upper armhole from it down to join the original curve about a third of the way down. The armhole becomes slightly shorter and a little steeper, which is tolerable for a small amount, and the sleeve can be eased in a touch more.

Tip: Do the adjustment on the paper pattern, not on the cut fabric. Moving the shoulder point on a cut bodice means recutting the armhole, and the hinge method does not work on fabric.

Does the sleeve need to change?

With the pivot method, no. The armhole has the same length, so the sleeve cap fits with the same ease. If you used the redraw method and the armhole is now shorter, reduce the sleeve cap by the same amount: take a vertical tuck through the center of the cap, as deep as half the difference, tapering to nothing at the hem of the sleeve. The guide to setting in sleeves explains how to check that the cap and the armhole match before you sew.

What about drop shoulders, raglans and kimono sleeves?

A drop shoulder is drafted to extend past the bone, so the adjustment does not apply; if the drop is more than you like, shorten the shoulder seam by the extra and shorten the sleeve length by nothing, since the sleeve is measured from the dropped point. On a raglan there is no shoulder point to move; a narrow shoulder shows as fullness at the top of the raglan sleeve, and the fix is a deeper dart or seam along the shoulder line of the sleeve. Kimono sleeves do not care.

Does made-to-measure drafting fix narrow shoulders?

Yes, this one is done upstream. Shoulder width is one of the few body measurements that a pattern drafted from your numbers places exactly: a made-to-measure bodice ends its shoulder seam at your shoulder bone because that is the number it was drawn from, independent of your bust size. Sewly measures the shoulder width across the back, from bone to bone, and draws the shoulder point and the armhole from it, so the narrow shoulder adjustment is not needed on its patterns. Measure carefully, since a 2 cm error in the shoulder width is exactly the problem this post is about. Shoulder slope and back width are not measured and are still checked on the first toile; the custom-fit sewing patterns page lists what the draft takes from you.

Common mistakes with the narrow shoulder adjustment

  • Cutting the shoulder seam shorter and redrawing the whole armhole. The armhole loses length, the sleeve no longer fits and the underarm rises. Pivot instead.
  • Taking the width off at the neck end. The neckline shrinks and the shoulder point stays where it was, on your arm.
  • Measuring the shoulder width from the front. The front shoulder width is smaller than the back; patterns and measurement charts use the back.
  • Doing it on an intentionally dropped shoulder, which turns a relaxed design into a tight one with an armhole that binds.
  • Forgetting that a size down is not the same thing. Going down a size narrows the shoulders a little and everything else a lot. Alter the shoulder and keep the size that fits the bust.