Sloping shoulders show as diagonal folds of loose fabric running from the base of the neck down toward the armhole, with the shoulder seam standing away from your shoulder at its outer end. The fix is to lower the shoulder seam at the armhole end, usually by 1 to 2 cm (3/8 to 3/4 in), tapering to nothing at the neck, and then lower the armhole by the same amount so the sleeve still fits. It is a five-minute alteration on the front and back bodice, and the sleeve pattern does not change.
How do you know you have sloping shoulders?
Put on a toile, or a close-fitting woven top, and look at the shoulders in a mirror with your arms relaxed. The signs of a shoulder that slopes more than the pattern allows for are:
- Diagonal folds from the neck toward the armhole, on the front and the back. The fabric is too long on the outer shoulder, so it collapses into folds that point at the neck.
- A gap under the outer end of the shoulder seam. You can slide a finger between the seam and your shoulder near the armhole.
- The armhole hangs low and the sleeve cap stands up in a point above your shoulder, since the whole outer edge of the bodice is sitting lower than drafted.
- Wide necklines slip toward the shoulders.
The folds are the giveaway. Width problems create horizontal or vertical lines; a slope problem creates diagonals that start at the neck. The post on how to read drag lines compares them with the lines of a too-narrow shoulder or a tight bust, which can look similar at a glance.
Most sewing patterns are drafted for a shoulder slope of about 20 to 22 degrees from horizontal, which is an average. If yours is steeper, every pattern you buy will need the same fix, which is why it is worth measuring once and writing the number down.
How do you measure your shoulder slope?
The simplest way does not need a protractor. Stand against a wall with a tape measure or ruler held horizontal at the base of your neck, at the side, where a necklace would sit. Measure straight down from that horizontal line to the tip of your shoulder bone. On a pattern, measure the same drop on the front bodice: from a horizontal line through the neck point down to the shoulder point. The difference between the two numbers is the amount to lower the shoulder seam.
The most reliable way is on a toile. Pin the shoulder seam open at the armhole end and let the back and front settle until the folds disappear. Then pin the seam closed where it now wants to lie and measure how far below the original seam line the new seam sits at the armhole edge. That measurement, taken on each side separately since many of us have one shoulder lower than the other, is the adjustment.
Typical amounts are 1 to 2 cm (3/8 to 3/4 in). More than 2.5 cm (1 in) is unusual; if you find that, check that the shoulder seam is not also too long, which the narrow shoulder adjustment fixes separately.
How do you adjust the pattern for sloping shoulders, step by step?
You need the front and back bodice pieces, a ruler, tape and a pencil. Work on a traced copy without seam allowances, or draw the stitching lines in first.
- Mark the drop at the shoulder point. On the front bodice, measure down from the outer end of the shoulder stitching line, along the armhole, by your adjustment (say 1.5 cm, 5/8 in). Make a mark.
- Redraw the shoulder seam from the neck point to the new mark. It is a straight line that now slopes more steeply. The neck end does not move.
- Lower the armhole by the same amount. Measure 1.5 cm down from the bottom of the armhole curve at the side seam and make a mark. Redraw the armhole from the new shoulder point down to the new underarm mark, keeping the same curve shape. Without this step the armhole becomes 1.5 cm shorter than the sleeve cap, and the sleeve no longer fits.
- Repeat on the back bodice with the same amount.
- Check the armhole length. Measure the front and back armhole curves on the stitching line and compare with the original. They should be within a few millimeters. The sleeve cap ease stays what the designer intended.
- True the side seam. Lowering the underarm shortens the side seam by 1.5 cm at the top; the side seams of front and back still match each other, so nothing else moves.
- Add seam allowances back if you removed them, and cut a new toile or the garment.
The sleeve is unchanged. The armhole is the same length as before, slightly lower on the body, which is exactly where your sloping shoulders put it anyway.
Tip: If one shoulder is noticeably lower than the other, alter each side by its own amount and cut the front and back as single-layer pieces, marking left and right. A 1 cm (3/8 in) difference between sides is common and shows as a seam that sits well on one side and gapes on the other.
What if the garment has a yoke, a raglan sleeve or no shoulder seam?
On a shirt with a yoke, the adjustment goes into the yoke piece: lower the outer end of its front and back edges, then lower the armhole on the shirt front and back. On a raglan, there is no shoulder seam to redraw; the slope lives in the top of the sleeve. Take a wedge out of the raglan sleeve along the shoulder line, 1 to 2 cm wide at the outer edge tapering to nothing at the neck, and lower the armhole on the bodice as above. Kimono and dolman sleeves rarely need this adjustment, since their looseness hides a slope.
Knit T-shirts show sloping shoulders less, but a fitted tee with set-in sleeves benefits from the same alteration, often in a smaller amount.
Square shoulders: the opposite adjustment
Diagonal folds that run from the shoulder point toward the neck, with the fabric pulling tight across the top of the shoulder and the neckline riding up, mean the opposite: your shoulders are squarer than the draft. Raise the shoulder point by the amount you need, usually 0.5 to 1.5 cm (1/4 to 5/8 in), and raise the underarm by the same amount. The logic is identical, only the direction changes.
Does made-to-measure drafting fix sloping shoulders?
Partly. A pattern drafted from your own measurements gets the shoulder width, the bust and the back length right, which removes most of the reasons a bodice can look wrong at the top. The slope is different: it is an angle, not a girth or a length, and it is not a measurement most people take or that a measuring assistant can check against your height. Sewly drafts from your shoulder width, back waist length and front waist length, so a made-to-measure bodice from it will sit well across the shoulders and at the waist, but if your shoulders slope more than average you will still see the diagonal folds on the first toile and lower the shoulder point as described above. Keep that number with your measurements: it applies to every future bodice, dress and jacket.
For a first test, the guide to making a toile explains what to cut, how to mark it and what to look for; the guide to fixing common fit issues covers the other problems you may spot at the same time.
Common mistakes with the sloping shoulders adjustment
- Forgetting to lower the armhole. The sleeve then has too much cap ease and puckers, and the underarm feels high and tight.
- Taking the whole amount at the neck end as well, which simply shortens the bodice by that amount and keeps the folds.
- Confusing it with a narrow shoulder. If the shoulder seam reaches past your shoulder bone, shorten it first, then look again at the slope on a fresh toile.
- Altering only the front. The back has the same slope and the same folds; do both.
- Doing it on a knit without need. Loose tees and sweatshirts do not show a slope. Save the alteration for fitted woven garments and anything with a set-in sleeve.