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10/31/2026

Most Common Pattern Adjustments: Shoulders, Broad Back, and Bust

If you've ever finished a garment only to find that it pulls across the back, the neckline gapes, or the shoulders slump, it isn't that you sew badly: the pattern simply doesn't fit your body. The most common pattern adjustments focus on three areas: shoulders, back, and bust. Learning how to alter them is what separates a "homemade" look from a garment made to fit you.

Before You Touch the Pattern: Take Measurements and Make a Muslin

No adjustment works without real data. Before cutting into the paper, write down these measurements:

• Shoulder width (from the base of the neck to the shoulder point).
• Back width, measured between armholes about 10 cm (4 in) below the nape of the neck.
• High bust measurement (above the bust) and full bust measurement.
• Bust height (from the shoulder to the bust point).

Next, make a muslin from inexpensive fabric. Mark the bust, waist, and hip lines on it. That way you'll see exactly where the wrinkles form and can make precise corrections instead of guessing.

Shoulder Adjustments: Sloping, Square, and Broad or Narrow

The shoulders are the foundation of how the whole garment hangs, so it's best to start with them.

Sloping shoulders. If you see diagonal wrinkles running from the neck toward the shoulder, or the shoulder seam slides downward, you need to lower the shoulder line:

1. Mark the shoulder point on the pattern.
2. Measure how much excess there is in your muslin (usually between 0.5 and 2 cm, or about 1/4 to 3/4 in).
3. Lower that point by the measured amount and redraw the line from the neck.
4. Readjust the armhole and check that the sleeve cap still fits.

Square or high shoulders. Here the opposite happens: the fabric pulls near the neck and horizontal wrinkles appear. Raise the shoulder point by the necessary amount, redraw the line, and add that same height to the sleeve cap.

Broad or narrow shoulders. If the seam falls outside your natural shoulder, change the length of the shoulder line and then correct the armhole. Always make sure the front and back shoulder seams are the same length so you can sew them together without easing or forcing.

Broad Back Adjustment

A broad back adjustment is one of the most frequent pattern alterations for people who swim, lift weights, or simply have a more developed upper back. The symptoms are clear: the fabric pulls between the shoulder blades, the garment wrinkles horizontally, and raising your arms feels restrictive.

To widen the back using the slash-and-spread method:

1. Draw a vertical line from the middle of the shoulder to the hem, parallel to the center back.
2. Cut along that line without separating the piece completely; leave a small hinge at the hem.
3. Spread the piece open by 0.5 to 1 cm (1/4 to 3/8 in). Remember that this amount doubles when you sew two back halves together.
4. Tape paper underneath and redraw the shoulder line and armhole with a smooth curve.
5. If the shoulder ends up with excess length, absorb the difference with a small dart or a little ease when sewing.

Don't forget to check the sleeve width: if you widen the armhole, the sleeve cap will need to be adjusted so the whole garment stays balanced.

Bust Adjustment: More or Less Volume

When your bust is fuller than the pattern allows for, wrinkles pointing toward the bust appear, the front hem rides up, and buttons gape open. The solution is the full bust adjustment (FBA):

1. Choose your size based on your high bust measurement, not your full bust, so the shoulders and neckline fit well.
2. Calculate the difference between the two measurements and divide it by 4: this is the amount you need to add to each half of the front (subtract whatever the pattern already includes in its base cup size).
3. Mark the bust point and draw lines toward the center of the shoulder, the armhole, the side seam, and the hem.
4. Cut, spread the piece open by the calculated amount, and add paper underneath.
5. Redraw the dart, now larger, and add length to the hem to make up for what has been "used up."

If, on the other hand, you have a smaller bust, follow the reverse process: close the piece along the same lines and reduce the dart. Always check that the dart points toward the bust point, slightly above the actual apex.

Tips to Make Your Adjustments Work

• Correct one area at a time and test the fit before moving on.
• Save your modified base pattern so you can reuse it in future projects.
• Note each change with the date and measurement; your future self will thank you.
• Check that the seams being joined are the same length after every alteration.

Conclusion

Mastering these pattern adjustments lets you pick any pattern with confidence and adapt it to your body, without settling for "it almost fits." With a good muslin, precise measurements, and patience, shoulders, back, and bust stop being a problem.

Want to keep practicing? Explore the rest of our pattern-making and drafting articles at allsewingpatterns.com, download our basic block patterns, and tell us in the comments which adjustment gives you the most trouble so we can prepare the next guide.

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