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Plus-Size Pattern Fitting: All About the Vertical Adjustment

When fitting a sewing pattern, we’re accustomed to checking the standard measurements such as bust, waist and hip. What do these have in common? They are all measurements of circumference. But there’s another dimension that is critical to getting a good fit: the vertical dimension.

These vertical measurements are not marked on most patterns, but you can measure and adjust your patterns in both dimensions to get a good fit and be more comfortable in the clothes you make.

two dress forms

So where to start? Read on to find out how to use vertical adjustment for a pristine plus-sized fit!

These two dress forms pictured above illustrate the potential need for vertical adjustment on sewing patterns.

The light pink form on the left shows how bust depth, which is the distance from the top of the shoulder to the bust apex, is considerably longer with a plus size figure or full busted figure. The horizontal line marks the bust apex on both dress forms, and that is the point on your pattern where you want the maximum fullness to accommodate the curves there.

Imagine a pattern with bust darts that would finish near that apex, closer for the less full bust and further away for the more full bust. So, based on the measuring tape, even though they may be the same height, the full busted form needs more length in the front to reach the waist.

Often wrap-style dresses or tops don’t include a side dart, so here is a way to adjust the pattern front and create the extra length that is needed.

Step 1: Evaluate the pattern

bodice front pattern

Here is the front bodice pattern piece which is a mock wrap front with shoulder darts. The bust apex is indicated on the pattern as the small circle with the +. The center front is marked and that should be transferred to your pattern, so that your wrap overlaps properly. There is no side bust dart but that will be added to create some shaping and allow for the longer front measurement from shoulder to waist.

Step 2: Make a muslin

bodice example

The test version of our pattern shows that the pattern circumference is good. It appears to fit going around the body, but the issue with bodice length is clear. The yellow dots represent the bust apex on the pattern and they are about 2″ higher than the actual apex of the form, which is shown by the upper ribbon.

The bodice is also pulling upwards under the bust, so the garment waist will not be in the right place.

Here’s what to do next:

  • Measure the distance between the pattern mark of the apex and the actual apex. This will be the distance that the pattern will be lengthen over the bust.
  • Now, measure the distance between the bottom of the bodice and the waist.
  • If that is more than the difference you will be adding at the bust, you may want to add a little more at the bottom edge as well, or deepen your seam allowance to permit some adjustment when you sew the top and bottom together.

Step 3: Split the pattern piece

draw line on pattern piece

Draw a horizontal line across the pattern, through the apex or just under as shown. Be sure that line is perpendicular to the grainline. Add a few vertical lines across this horizontal line, which are used to connect the pattern piece after you split it. Cut the pattern piece in half using this line.

Step 4: Lengthen the pattern piece

split pattern piece

Insert paper between the now split pattern pieces, in this case we have added 2 inches across the front bodice which. Connect the vertical lines to keep everything even, including the grainline.

Step 5: Adjust the front cutting line.

adjust front pattern edge

By adding the 2″ in the middle of the bodice, the long front edge is now a bit jagged. Smooth that edge by redraw the cutting line, splitting the difference above and below the inserted piece.

Step 6: Add a dart

adding bust dart

With the added length the front bodice is 2″ longer than the back bodice piece at the side seam. To take up that difference add a side bust dart. This kind of dart is really helpful to get a good fit on a full bust so don’t be afraid to add one where none exists.

Note that the dart point should be about 1.5″ to 2″ away from the bust apex. I find a dart that’s slanted upward is more pleasing to the eye than one that’s completely horizontal. It also helps to pin your paper pattern pieces together and test on the body, you can pinch out the extra and see just where the side dart should go. Make sure the front and back bodice seams are trued up and you are ready to try a second muslin.

Step 7: Make a muslin to test your adjustments

muslin with better fit

Here’s the new muslin of this pattern, with the bodice length adjustment and a side seam bust dart added. The bottom of the bodice hits at the waist, and retains the ease and blousing of the pattern design. The new dart is creating fullness where it is needed over the bust and allowing the fabric to drape instead of pulling the waist seam upward.

Time to sew your garment!

striped maxi dress

With those adjustments the bodice drapes nicely, the soft blousing is maintained and the dress is going to be much more comfortable to wear than it would have been without the front length adjustment. And no tugging to try to get that waist seam to stay in place.

Are you going to think vertical next time you try on a muslin, and evaluate whether some added bodice length will result in a better fit? Let me know.

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Don’t you have to drop the apex? I see you added length and made a dart to make up the difference, but the apex was originally high and the dart goes to the original high apex, instead of the dropped apex. I’m confused.


That is correct, the dart should point to the actual apex, That is why I suggest tissue draping or making a bodice muslin and pinching the fabric to see where the dart should actually go.

Sueann Walter

beth, you said to draw a line perpendicular to the grain line, but your line was perpendicular to the center front line. Did you mean center front line? And I have the same question as Karen above – should you point the dart to the new apex?


Hi Sueann, good catch! with this pattern the grain line is diagonal so it would be correct to create the split line perpendicular to the center front line. More frequently the grain line is vertical so that does make it more apparent how to draw that horizontal line to add the length. And yes, the dart should point to the new apex which moves downward . Thanks for the question.


Thank you for this tutorial. It will be helpful for me.


I have several wrap dress patterns, so this article will prove to be very helpful to me. One question: what full size dress form are you using? My current one is from when I was 21 and a size 12! I now need one for a mature, plus size figure. I would appreciate knowing what brand and type you find to be the best.


HI Koushite, glad you found this helpful. As for dress forms, I don’t have any specific recommendations but some advice. The form you see in the photo started out as an adjustable “full figure” dress form. I then padded it out to create the circumference measurements needed. My tip – put the correct size bra on the form, and adjust so the bust apex is at the right level. usually lower than the form. It may mean that the straps are too short so just pin the cup portion in the right place and skip the bra hooks. Then pad out the bra and use batting or wrap terry towels to pad out the rest. I cover with some knit fabric and then have a “customized” dress form. Good luck.

Edie Scott

Is there anyway to enlarge jeans waistband when the jeans fit perfectly everywhere else?


what a shame you didn’t post last week, I cut out and tacked a dress for my daughter. I tried to fit this morning but she has a fuller bust than me and the bodice didn’t fit her and was short on the armholes so I am adjusting it for me. I will know what to do next time but I owe her a dress now as I’ve pinched hers


OK so you make it clear about the vertical – what about the horizontal? At the same time if adapting for a large bust you need width as well as length, but nothing is said about width.

Ada Hathaway

Based on the first muslin, Beth knew that the circumference was OK. It took me a long time to figure out that the circumference could be OK but the length is still to short. Kathleen Cheetham’s class, Adjust the Bust” taught me this important fitting adjustment.

Jean Munn

Hi, looking for advice on extending a wrap top by 4 inches. I am using the Sew Over It pattern Blossom maternity top for my daughter who is pregnant and 6 feet tall. When I lengthen the bodice, the wrap front didn’t sit right.

Mary D

Also for plus adjustments one may need to adjust the back length of a garment such as a skirt or dress to accommodate ample hips so that the dress/skirt is not raised in the back over the hips. A slight circular addition adjustment to the bottom length of the dress/skirt can account for this.


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