how to do a broad shoulder adjustment

Do you have broad shoulders? If your tops feel tight across the shoulders, you may need a broad shoulder adjustment.

A garment that is too narrow in the shoulders can pull at the armhole seams. The sleeves may look distorted, and if it’s a short-sleeved garment, they may flare out at the hems instead of sitting close to your arm.

Luckily, there’s a very simple fix.

How to do a broad shoulder adjustment.

Broad shoulder adjustment tutorial: How do you know you need one?

I have been mulling over how to demonstrate fit issues that I don’t personally have. While browsing an online store, I came across a garment image that perfectly illustrates the need for a broad shoulder adjustment.

How can you tell if you need a broad shoulder adjustment?

The first clue for me was the way these t-shirt sleeves flare out at the hem. They don’t lay nicely because too much of the fabric is curved over the shoulder. If the shoulder were dropped, the hem would fall properly and the sleeve wouldn’t stick out.

My second clue was in what appears to be a drag line that was retouched. On the model’s left side, there is a dark spot that I suspect is a Photoshopped wrinkle that points to the shoulder. I’ve pointed it out in the image below. This type of drag line indicates that the shoulder is too narrow.

How do I know if I need a broad shoulder adjustment?

Determining how much to adjust

Generally speaking, the shoulder seam on a pattern with a regular (not intentionally dropped) shoulder should hit at about the ball of your shoulder, where it hinges when you lift your arm. You can measure the difference by making a quick muslin and seeing where the shoulder seam falls on you. Or you can eyeball it by holding up the pattern piece to your body. Once you know how big your adjustment should be, it’s time to mark and slice your pattern.

Broad shoulder adjustment tutorial steps

Step 1: Prepare your front bodice piece for cutting. To do this, mark the center point of the shoulder seam with a dot on the seam line. Make another dot on the seam line about 1/3 of the way down the armscye.

How to do a broad shoulder adjustment.

Draw a line along the dots from one edge to the other (indicated by the purple line below). Draw another line from the corner to the line you just drew (indicated by the green line below). This line should be perpendicular to the first line.

Broad shoulder adjustment tutorial.

Step 2: Next, cut along the purple line, starting from the shoulder seam and cutting to, but not through, the armscye. Leave a small paper “hinge” so that you can pivot the pattern in the next step.

How to do a broad shoulder adjustment.

Step 3: Next, cut along the green line, starting from the cut you just made and ending at the outer corner of the shoulder seam. Cut to, but not through, the outer corner, again leaving a paper hinge.

Broad shoulder adjustment tutorial.

Step 4: Slip a piece of paper under your pattern. A scrap is fine for this purpose. We are going to spread the pattern piece along the cut purple line. The distance we spread it will be equal to the amount of your adjustment, measured on the seam line. (Hint: It helps to spread it a little, and then tape down the pattern piece on the side of the purple line that is closest to the neckline.)

In this case, I made a mark on my scrap paper that was 1/4″ from my cut, shifted towards the armscye. I made sure to keep it even with the seam line.

How to do a broad shoulder adjustment.

Step 5: Connect the dots. Move the slashed pieces away from the neckline, widening the shoulder, until the edge of the cut purple line meets your new dot and the shoulder edge makes a straight line. The slash in the corner of the shoulder will overlap a bit as you do this. The end result is to widen the shoulder seam while keeping the armscye length intact so you don’t have to adjust your sleeve.

Broad shoulder adjustment tutorial.

Tape the pieces in place. Now repeat this procedure on the back bodice, and you’re done!

How to do a broad shoulder adjustment.

And that’s all there is to it! If you’re interested in more fitting tutorials and general fit-related geekiness, check out our library of fitting resources and our tutorials tag. Happy fitting!


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  1. Hanna

    This is so helpful! If you also need to do a full bust adjustment, in wich order would you do it? Bust first or shoulder first? I’m in the unfortunate situation that I have a tiny ribcage, fairly busty and very broad shoulders. This means my over bust measurement is almost the same as my full bust measurement, while the underbust measurement is tiny…

    1. So the basic answer is that I would probably start with the shoulders and then do the bust. But I’m also curious as to where you start when choosing your size, if you’re adjusting for both broad shoulders and full bust. There may be a more efficient way to fit!

      1. Hanna

        Thank you for your answer! There are probably easier ways to do it, or maybe choosing different patterns… if I choose my size by my shoulders I would have to go up several sizes, or choose a pattern for men’s clothes. I usually try to choose by bust-size if available. It just tend to be to large over my belly and lower back because of the imbalance. I’ll have to do some more experimenting!

    2. jax

      Hi Hanna, you may want to split your size. So, if your front measures for a size 12, but your back is a size 10 or 8, do that. Then you won’t have a billowy back on your garment.

  2. NatalieJSP

    Thank you for this!

  3. Meta

    Thank you for the tutorial.
    I used this technique recently on the Metro T-Shirt. After increasing the shoulder length for a little more than an inch the armscye curve got shaped in form of a flattened number 3. The curve was the same length as before so I set the sleeve in as usual. But when wearing the T-Shirt there is some weird peak in the fabric at the top of the sleeve, I assume it’s due to the deformed shape of the armscye curve. Do you have any advice how to fix that, please?

    1. It’s hard to tell without seeing the pattern piece. I’m having a hard time visualizing how it could have turned into a number 3 shape using this method. Although 1″ is quite a large adjustment, the armscye should still be just one curve. I have a few ideas. 1) Whatever the reason the curve ended up a little wonky, you can always just smooth it out a bit. 2) If the curve is very wonky, you might want to start a size up in the shoulder and then do a smaller broad shoulder adjustment. 3) Finally, you could post a photo of your pattern piece in our forums and we could take a look and help troubleshoot.

  4. Amanda Correa

    Thank you, Masha. This is helpful and something I need to practice.

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