Step 1: find the size for your larger side
Measure as usual. A tape goes around both breasts, so the result is an average and may come out slightly small for the bigger side. Try the calculated size and one cup above it.
Judge the fit on the larger breast only. After a scoop and swoop, that side should have no ridge at the top of the cup, the wire should sit on rib at the side, and the centre panel should lie flat.
Step 2: adjust the smaller side
- Shorten the strap on the smaller side. For a small difference this is often all that is needed.
- Add an insert. A foam or silicone pad, sometimes sold as a "cookie" or enhancer, sits in the bottom of the cup and takes up the spare room. Many bras have a pocket for one.
- Remove a pad from the other side. If the bra comes with removable pads, take out the one on the larger side and keep the other in.
Styles that help
| Style | Why it works |
|---|---|
| Stretch-lace upper cup | The top of the cup stretches to fit the fuller side and lies flat on the smaller one |
| Unlined seamed cups | Soft fabric follows each breast and does not hold an empty shape |
| Removable-pad or pocketed bras | Padding can be different on each side |
| Lightly padded balconette | Lower-cut cups leave less empty space to show |
| Non-wired and bralette styles | Flexible throughout, for small to moderate differences |
Styles that make it more obvious
Firm moulded T-shirt bras keep their shape whether or not they are filled, so the smaller side shows as a dent or a gap. If you like a smooth moulded look, choose one with removable pads or use an insert.
If the difference is a cup size or more
The same approach works, with a larger insert. Partial prostheses, sometimes called shapers or balancers, are made for exactly this and come in graded sizes. They are worn inside a pocketed bra. Specialist lingerie shops and mastectomy-wear retailers can fit them, and you do not need to have had surgery to buy one. See post-mastectomy bra fitting for where to find a fitter.
What not to do
- Do not fit the smaller side. The larger breast will be compressed and spill, and the band and centre panel will be pulled off line.
- Do not split the difference. A cup that is slightly too small for one side and slightly too big for the other fits neither.
When to see a GP. A long-standing difference is normal. See your GP if one breast has recently changed in size or shape, or if you notice a lump, skin dimpling, nipple changes or discharge.
Frequently asked questions
Is it normal for one breast to be bigger than the other?
Yes. Some difference between the two sides is the norm, and a difference of up to a cup size is common. A sudden or recent change in the size or shape of one breast is different, and should be checked by a GP.
Which breast should I fit my bra to?
The larger one. A cup that is too small for one side will dig in and push the whole bra out of position. A slightly roomy cup on the smaller side is easy to correct with the strap or an insert.
What bras are best for asymmetrical breasts?
Bras with stretch in the cup, particularly a stretch-lace upper section, adapt to each side. Bras with removable pads let you take one out. Rigid moulded cups show a difference most.
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