A Small Bust Adjustment (SBA) removes excess fabric from the bust area of a sewing pattern while keeping the fit through the rest of the bodice. It is useful when a pattern fits well elsewhere but has too much room around the bust.
In this guide, you’ll learn how to tell when you need an SBA, determine how much fabric to remove, and adjust both darted and dartless bodice patterns. If you’re working with a Winslet’s sewing pattern, understanding this adjustment can help you fine-tune the fit to your measurements without changing the areas that already fit well.
What Is a Small Bust Adjustment?
A Small Bust Adjustment reduces the pattern specifically at the bust when there is more fabric than your body needs. The goal is to remove that excess while preserving the fit through areas such as the shoulders, upper chest and waist.
An SBA may be needed when you notice excess fabric in the bust area, while the rest of the garment fits correctly.
How do you know if you need an SBA?
Look for:
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Vertical puddling or bubbling of fabric around the bust.
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Horizontal excess fabric across the bust.
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A bust area that does not lie smoothly against the body.
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A garment that fits well everywhere else but feels too loose around the bust.
You may also know you need an SBA before making a test garment if the difference between your high bust and full bust measurements is smaller than the difference the pattern was drafted for.
How Much Should You Remove for a Small Bust Adjustment?
The amount to remove depends on the difference between your body measurements and the pattern measurements, including the ease you want in the finished garment.
In pattern drafting, cup size refers to the difference between your high bust and full bust measurements. It is not the same as bra cup size. A 1-inch difference corresponds to a pattern A cup, a 2-inch difference to a pattern B cup, and a 3-inch difference to a pattern C cup.
For example, if your high bust-to-full bust difference is 1 inch but the pattern was drafted for a 2-inch difference, you already know that approximately 1 inch needs to be removed from the bust.
However, cup-size comparison is not the only way to determine the adjustment. If the pattern provides finished garment measurements, compare them with your body measurement plus your desired ease.
How does ease affect an SBA?
Ease is the additional room built into a garment beyond your body measurements. Wearing ease allows you to move comfortably, while design ease creates additional volume for a particular style.
The source guide gives these minimum bust-ease ranges:
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Blouses, dresses and jumpsuits: 2½–3 inches (6½–7½ cm)
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Unlined jackets: 3–4 inches (7½–10 cm)
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Lined jackets: 3½–4½ inches (9–11½ cm)
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Coats: 4–5 inches (10–12½ cm)
Thicker fabrics generally require more wearing ease, as do garments designed to be worn over other layers.
Check the Bust Apex Before Making an SBA
The bust apex is the fullest point of the bust, and the pattern's apex should ideally line up with yours. Check this position before making the adjustment because the bust shaping may need to be raised or lowered first.
If you have a tissue pattern, you can place it against your body to compare the apex locations. Pay attention to the centre front and seam allowances so the pattern is positioned correctly. If the pattern apex is more than about half an inch away from your bust apex, it should be adjusted before making the SBA.
You can also establish the apex by measuring from the mid-shoulder to the fullest point of your bust and then measuring from the centre front to that point. Transfer those measurements to the pattern, excluding seam allowances.
Once your apex is marked, measure across the pattern at bust-apex level. Exclude the seam allowance and, where appropriate, fold out the dart while measuring. Compare the complete front and back pattern measurements with your body measurement plus the desired ease.
If you have already sewn a test garment, you can determine the amount to remove by pinning out the excess fabric evenly across the bust. Do not overfit the garment: you still need enough room to move comfortably, and the centre front should remain at the centre front while the side seams stay in their correct position.
Measure the amount pinned out on both sides. Double the depth of each individual pinch to find the total removed from that side, then add the amounts together. If the amounts are different on each side, divide the total to determine the average amount to remove from each half of the front.
How to Do a Small Bust Adjustment on a Darted Bodice
A darted bodice uses a slash-and-overlap method to remove excess width from the bust while maintaining the rest of the pattern shape.
Step 1: Mark the adjustment lines
Start with your pattern or a copy with the bust apex marked.
Draw these lines:
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A line parallel to the grainline from the waist or hem to the apex.
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A line from the apex to a point somewhere in the lower third of the armhole.
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A line through the centre of the dart toward the apex.
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A line perpendicular to the grainline from the edge closest to the centre front to the first line, somewhere near the waist or hem.
The exact height of the horizontal line can vary.
Step 2: Cut the pattern
Cut from the waist or hem to the apex. Turn at the apex and continue toward the armhole, stopping just before the edge so a small paper hinge remains.
Cut along the dart line toward the apex, again leaving a small hinge.
Then cut completely across the horizontal line. Keep the piece you cut off because you will use it when reshaping the pattern.
Place a piece of paper underneath the open section.
Step 3: Overlap the pattern
Overlap the side section of the pattern over the centre section by half the total amount you need to remove.
For example, if you need to remove 1 inch from the total front, overlap this half-front pattern by ½ inch.
Keep the overlapped edges parallel and the same distance apart along the adjustment. Tape the pieces in place.
Because the pattern represents only half of the front bodice, removing half of the total amount from this piece results in the required total reduction when the garment is sewn.
Step 4: Realign the waist or hem
The overlap changes the position of the waistline because the pattern no longer needs as much fabric to travel over the bust.
Bring the loose centre section into alignment with the side section at the waist or hem and tape it in place.
The waist width will also become smaller after the reduction. If you need to retain some of that waist room, add it back at the lower side seam. The additional room can be divided between the front and back if needed.
Step 5: Redraw the dart
The dart will automatically become smaller after the SBA, but its new position still needs to be checked.
The dart should point toward the bust apex. For a smaller bust, the new dart point should finish approximately ¾–1 inch away from the apex.
To establish the new dart:
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Measure back approximately ¾–1 inch from the apex.
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Mark this as the new dart point.
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Draw the new dart legs from the dart base to the new point.
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Fold the dart by bringing the lower leg up to meet the upper leg.
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True the seam at the dart base so the two sides blend smoothly.
When truing the dart base, remove half the difference from the larger side and add half to the smaller side. The resulting lines should flow smoothly from the original seam lines.
Step 6: Check the side seam
With the dart folded, cut or redraw the side seam to create its new shape.
Then compare the altered front with the back pattern piece. Line up the side-seam notches and check the seam line—not simply the cut edge—to make sure the front and back are the same length.
How to Do a Small Bust Adjustment on a Dartless Bodice
A dartless bodice can use a simpler pivot method to remove excess room at the bust while keeping the waist unchanged.
Step 1: Trace the pattern
Trace the outline of the bodice onto another piece of paper. Mark the seam line around the shoulder and armhole so you know where the actual seam sits.
Step 2: Mark the amount to remove
At the armhole side seam, measure inward by half the total amount you need to remove from the bust and mark the new point.
Step 3: Pivot the pattern inward
Place the original pattern over your tracing and hold it at the intersection of the shoulder and armhole seams.
Pivot the pattern inward until the underarm reaches the mark you made.
Keep the pattern in position and retrace the new armhole.
Step 4: Restore the side seam
Move your pencil or awl to the pattern's armhole and side-seam intersection. Use this point as the pivot and move the pattern back until the side seam meets its original position at the waist.
Trace the new side seam.
The result is a pattern that has been reduced at the bust while retaining the original waist position.
Step 5: Check the side seam length
The side seam may need to be raised at the waist to return it to its original length. Compare the adjusted front with the back bodice pattern at the side seam to make sure the pieces remain the same length.
Can Dart Position Affect Whether You Need an SBA?
Yes. Sometimes changing the position of the bust shaping can improve the fit without requiring a full adjustment.
The location of the bust dart in relation to the apex can make a significant difference, particularly in garments with a lot of design ease. Before making an SBA, check whether the bust shaping itself is correctly positioned for your body.
If you'd like to see this adjustment demonstrated step by step, you can watch the video below.
Refine the Fit of Your Next Sewing Project
A Small Bust Adjustment is useful when a pattern fits well through the shoulders, chest and waist but leaves excess fabric around the bust. By measuring carefully and removing only the amount you need, you can preserve the areas that already fit while improving the bust fit.
As you work through Winslet's sewing patterns, understanding adjustments like the SBA can give you more control over how a pattern fits your individual measurements.
Explore Winslet's sewing pattern collections and find your next project to fit and sew with confidence.
FAQs
What is a Small Bust Adjustment?
A Small Bust Adjustment removes excess fabric from the bust area when the rest of the garment fits well but the bust is too loose.
How much fabric should I remove?
Compare your body measurements plus your desired ease with the pattern or finished garment measurements. If you use a test garment, pin out the excess fabric across the bust and measure how much has been removed.
Do I remove the full amount from one side of the front?
No. Because a front pattern piece represents half of the front bodice, remove or overlap half of the total amount on each half-front pattern piece.
Can I do an SBA on a pattern without a dart?
Yes. A dartless bodice can be adjusted using the pivot method. The reduction is made at the bust while keeping the waist position essentially unchanged.
Should I check the bust apex before an SBA?
Yes. The pattern's bust apex should correspond closely with your own. If it needs to be raised or lowered, make that adjustment before performing the SBA.
