A sleeveless dress can feel roomy through the body while still being uncomfortable at the armholes. An edge may rub, stand away from the chest or reveal more at the side than you expected. These details deserve a separate fitting check because adding a cardigan only hides them temporarily; it does not change how the dress fits underneath.

Start with the underwear you intend to wear and the straps adjusted as the design allows. Stand naturally with your arms down. Holding your arms away from your sides can disguise rubbing, while pressing them tightly against the dress can hide an opening. Use your ordinary posture as the reference.
Inspect the armhole from the side
A front mirror view often misses the deepest part of the armhole. Turn slightly or use a second mirror to see how the edge follows the body. Notice whether the fabric lies comfortably, cuts inward or forms a pronounced opening. Decide what side coverage you actually want rather than assuming every sleeveless design should sit equally high.
A lower armhole can be an intentional part of a relaxed cut. If you enjoy that shape, choose an underlayer whose visible edge feels deliberate. If you prefer the underwear to stay hidden, look for a different armhole depth instead of relying on an exact arm position throughout the day.
Check the bust and upper back together
Gaping near the front armhole does not always mean the whole dress is too large. The bodice shaping may not match where you need room, or the neckline and shoulder arrangement may affect the edge. Look for pulling across the chest or back before deciding to size down.
Likewise, an armhole that presses may involve insufficient room through the upper body rather than an isolated narrow opening. Reach forward gently and notice where the tension begins. If the chest pulls and the armhole digs at the same time, compare another cut rather than planning to trim the armhole without considering the rest.
Look for hidden construction problems
- A lining can pull the armhole edge inward even when the outer fabric has room.
- A facing may roll outward and make the edge appear thicker.
- A twisted strap can change the opening on one side.
- A rough seam or decorative edge can rub despite adequate space.
Adjust straps without moving the whole bodice
If straps are adjustable, make small changes and check both sides. Shortening them raises the armhole, but also lifts the neckline, bust shaping and waist. An adjustment that hides underwear may create pulling elsewhere. Choose the strap length that supports the dress’s intended position before judging whether its coverage meets your preference.
For fixed straps, do not assume shortening is a simple isolated solution. A tailor can assess what it would do to the armholes and bodice length. Thick straps, linings and decorative panels can complicate the change. Ask to see the proposed result marked on the garment while you wear it.
Move as you would during the day
Reach forward to a table, lift an arm to a comfortable shelf height and bring your hands together. Watch whether the armhole edge stays comfortable and returns to place. Some movement in the fabric is normal; persistent rubbing or a dress that remains shifted afterward deserves attention.
Try your usual bag on the shoulder too. Its strap can push the dress strap outward, opening the armhole more than expected. A crossbody can pull the bodice diagonally. Remove the bag and compare, so you can distinguish a dress issue from a particular accessory pairing.
Choose the most dependable solution
A smooth camisole can make an intentionally open armhole wearable when there is enough room for it and you like the visible layer. It will not remove pressure from a tight edge or correct a lining that twists. Choose an underlayer for coverage, not as a substitute for comfortable construction.
Before keeping the dress, check the side view once more after sitting and walking. The best option provides the coverage you chose and leaves your arms free without continual adjustment. A different neckline or shoulder design may solve the problem more completely than changing sizes repeatedly within a cut that does not work for you.
