Independent guide. We are not affiliated with either retailer. Experiences at both vary between fitters and stores. This page explains why results can differ. It is not a verdict on either company.
The two retailers
| M&S | Bravissimo | |
|---|---|---|
| Type | General retailer, the UK's largest bra seller | Specialist for D cups and above |
| Size focus | The whole range, densest in the middle | D to L cups, including small bands |
| Fitting | Free in store; method varies by fitter | Free in store; by eye, without a tape measure |
| Price level | High street | Specialist |
| Suits | A to E cups, everyday basics, convenience | D cups and above, particularly F and over |
Why the sizes differ
1. The method
If a size is worked out from a tape measure with inches added to the underbust, the band comes out larger and the cup letter smaller. If a fitter starts from how a bra sits on you and works down to the smallest comfortable band, the band comes out smaller and the cup letter larger. Research at the University of Portsmouth found the traditional tape-measure method overestimated the band in most of the women it tested. Individual fitters at any retailer may use either approach.
2. What each shop stocks
A fitter can only put you in a size on their shelves. A specialist stocks 28 and 30 bands with cups to K and beyond. A general retailer's range is thinner at those edges, so someone who needs a 30G may be offered the nearest size held, on a larger band.
3. The cut
Different brands, different patterns. Band stretch and cup depth are not the same, so even with an identical method you might differ by a cup between the two.
Comparing the two results
Put both sizes on the same band, using the rule that each band size down adds one cup letter for the same volume.
| Size given at one shop | Same cup volume on a 32 band | Size given at the other | Real difference |
|---|---|---|---|
| 36C | 32DD | 32E | One cup |
| 36D | 32E | 32F | One cup |
| 34DD | 32E | 32FF | Two cups |
| 38D | 32F | 32G | Two cups |
A jump from 36C to 32E looks like three cup sizes. In volume it is one. Most of the change is the band. The sister size chart will convert any pair.
Which one fits? Check for yourself
Put each bra on, on the loosest hook, and scoop and swoop.
- Band: level at the back, firm, and it stays put with the straps off your shoulders.
- Cups: no bulge at the top or sides, no empty space.
- Centre panel: flat on your breastbone.
- Wires: on ribcage all the way round.
The bra that passes is the right size in that brand. If the band rides up or you need the tightest hook from new, the band is too big, whoever recommended it. The checks are set out in how a bra should fit.
Can you use one shop's size in the other?
Use it as a starting point. If a specialist fitting has put you in a 32F, look for 32F at M&S, bearing in mind that not every M&S style is made in every size. Do not convert back to a bigger band to find stock. If your size is not there, that range does not cater for you.
Which should you go to?
- A to C cup: M&S, or another general retailer. Bravissimo does not make your size.
- D to E: either. Try both and compare.
- F and above, or a band under 32 with a D-plus cup: a specialist will have far more that fits.
More detail on each in our M&S guide and Bravissimo guide.
Frequently asked questions
Why did Bravissimo and M&S give me different sizes?
Three things differ: the fitting method, the range of sizes each stocks, and the cut of the bras. A smaller band from one shop comes with a higher cup letter, so the two sizes can look far apart while holding a similar volume.
Which size is right, Bravissimo or M&S?
Whichever bra passes the fit check on your body. A level, firm band on the loosest hook, cups that contain everything, and a centre panel that sits flat. If only one of the two does that, that is your size in that brand.
Is a 36C the same as a 32E?
Nearly. A 36C holds the same cup volume as a 32DD. A 32E is one cup size bigger than that, on a band four inches shorter.
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