How to Do a Full Tummy Adjustment

Are your pants or skirt tight across your tummy with the waistline dipping down at the front? Learn how to do a full tummy adjustment with this simple pattern fix.

If your pants or skirt are pulling tight across your tummy, you might need a full tummy adjustment. That said, always make a muslin first to check whether you actually need one—depending on how the garment is designed, it may fit just fine as-is.

Just like a Full Bust Adjustment, a full tummy adjustment adds both length and width to give your body the room it needs. Think of it as the FBA’s cousin for your lower half!

How to Tell If You Need a Full Tummy Adjustment

• Your garment feels tight across your tummy, with fabric pulling and bunching underneath
• You can see diagonal lines running from your tummy out toward the side seams
• The front waistline is dipping down into a V shape
• The tops of the side seams are being tugged forward

Measuring How Much to Adjust By

The ideal approach is to make a muslin and assess the following:

For width (Measurement 1): Unpick the center front seam over your tummy (or if there’s no seam, slash down the center front). Straighten out the side seams so they hang perpendicular to the floor, then measure the gap that opens up at its widest point. Divide this number by 2—that’s Measurement 1.

For position (Measurement 2): Measure how far down from the top of the leg the widest part of that gap is (i.e. the fullest part of your tummy) This tells you where to place your horizontal adjustment line.

For length (Measurement 3): Measure how far the front waistline has dipped down from where it should sit (nice and level, parallel to the floor). That’s Measurement 3. Note that sometimes this is hard to measure – in which case, assume ½” (1.2cm) is needed as a starting point.

Alternatively, you can measure around your tummy at the fullest point when sitting down, and measure around the pattern at the same point to compare (measure down from the waist to your fullest point to make sure you’re comparing the same spot). Calculate how much width you need to add to comfortably accommodate your sitting measurement (depending on your comfort level this could be assuming zero ease, or positive ease).

You can also measure the length from your waist to crotch, over your tummy, and compare that to the pattern in order to assess the length you need to add. Make sure you account for seam allowances on the pattern pieces when doing this assessment.

Full Tummy Adjustment on Pants

Note: if your pants have a fly extension, cut it off first at the center front, do the adjustment, and then re-attach at the end.

Step 1: Draw your seam allowances around the upper edges of the front leg pattern piece. Draw the following lines:

1. Vertical line down front leg, dividing the leg in half at the hem.
2. A horizontal line at the height of the fullest part of your tummy (measurement 2)
3. A diagonal line from where 1 and 2 intersect, up to the outer corner of the waist.

Step 2: Cut along Line 2, starting at the center front and continue up Line 3 until you reach the seam allowance. Snip in from the other side of the seam allowance to create a small hinge.

Step 3: Cut down Line 1 from the waist, stopping just before Line 2 to leave a small hinge.

Step 4: Spread the pieces apart so the horizontal gap has parallel sides—this gap should equal Measurement 3. As you spread things out, you’ll see a small triangular gap open up at the waist, and the upper crotch section will jut out past the lower section. Check whether this crotch gap matches Measurement 1. If it does, perfect! If not, break the hinge at the waist and shift the piece over until the gap is the right width, keeping the horizontal gap parallel.

Step 5: Trace your new pattern piece. At the top, gently smooth over the triangular gap—it will become slightly curved. At the center front, follow the new upper section down, then curve it gently back into the original center front seam.

Step 6: This adjustment adds width to the waist. If you want to keep that extra width, you’ll need to add the same amount to any waistband or waist facing the pants have. If you don’t want extra width at the waist, draw in a dart where the triangular gap opened up and sew it closed when you construct your garment.

Full Tummy Adjustment on a Skirt

Adjusting a skirt (or the skirt portion of a dress) follows the same principle, just simplified.

Steps 1–4: Follow the pants instructions above, but use the center front edge in place of the crotch seam. Again, if you need more room you can break the top hinge and slide the top piece over until you have the width you need.

Step 5: When tracing your new pattern piece, continue the upper center front section in a straight line all the way down to the hem. This adds a bit of extra room down the front and prevents the skirt from cupping underneath your tummy.

Steps 6–7: Same as for pants—either adjust your waistband to match the added width, or add a dart to remove it.

Full Tummy Adjustment on a Top

For a top, we recommend using the slash and spread approach.

You Did It!

No more pulling, dipping, or tightness across your tummy! Your garment will now drape smoothly over your curves.
Remember: if something doesn’t fit, it’s the pattern that needs to change, not your body. Your tummy is perfect just as it is!

Want to dive deeper into fitting? This adjustment and many more are covered in detail in Ahead of the Curve, our best-selling book on fitting for curves. And if you’d like in-depth video tutorials that go much deeper, check out Cashmerette Club‘s library of fitting masterclasses.