Online Bra Size Calculators: The Good, The Bad and The Hilarious – Part 2

by Estelle Puleston

Find part 1 here for calculators by, Linda’s Online, Bust’DD, Butterfly Collection, A Sophisticated Pair, Ewa Michalak, Gossard, Ann Summers, La Senza,, Babycenter, Figleaves, John Lewis and Debenhams.

A year ago I tried out a big bunch of online bra size calculators and sizing charts to see how accurate they were. I was told I was everything from a 32A to a 24FF which just goes to show how wildly inconsistent bra sizing methods are amongst brands and retailers – it’s no wonder really that a lot of women are unwittingly wearing the wrong size or are unsure about what size they should be in!

Well, that article has since gone on to be our most popular blog post of all time, and since I only dipped my toe in the sea of online bra size calculators I thought I’d bring you a part 2.

Before I get into this I just want to reiterate a point I made in part 1: just because one of these calculators gives me a size I don’t wear, that doesn’t mean it’s wrong (or that I’m in the wrong bra size). Sizing varies from brand to brand and two women with the exact same measurements can wear different sizes due to body type or just fit preference, as I explained here.


Bra Sizes That Actually Fit Me: 30F and 32E (I’m definitely more comfortable and supported in a 30F, but own enough acceptably-well fitting 32Es from brands that start at a 32-band that I’m counting this as one of my correct sizes).


The Good – Right, or Almost So

Marks and Spencer – 28F

On a recent trip to the Marks and Spencer’s lingerie department I saw signs advertising expert bra fittings, and this is a place that sells more bras to British women than any other brand. So I had high expectations from their recently-launched online fitting tool, and I’m glad to say that this was my closest match. The tool asks you to wear your best-fitting bra and then takes you through a series of questions about its style and how it fits, plus asks for your underbust measurement (it never asks for your overbust one) and a handful of other things such as whether you have narrow, medium or broad shoulders. The only thing that surprised me was that it gave me a 28 band size despite me inputting that my best-fitting bra is a 30 band that lies straight and doesn’t dig in.

Linda The Bra Lady – 28DD or 28E

Kudos to this calculator for giving two sizes (that aren’t sister sizes) and explaining that my size will vary between brands and styles. It’s still a band and cup size too small, but it’s pretty close and a good starting point to try bras on if I had no clue as to my size.

A Bra That Fits – 26F/FF (with a note a 28E/F may fit better)

This calculator, unlike any other, takes into account how much ‘squish’ you have around your ribs by asking for your ‘snug’ and your ‘tight-as-you-can-make-it’ underbust measurements and using the difference between them to calculate how tight or loose a band you’ll need. Because the difference between those two measurements for me was less than an inch it said I may feel more comfortable sister sizing up to a 28E/F, which was helpful. Like the calculator above, it also gave me two possible cup sizes to try since sizing varies between brands.


The Bad – Well, the ‘Less Good’ (These Calculators May Work for Many Women)

Britney Spears Intimates – 28D

Being a European rather than UK-specific site, this actually gave me my ‘European’ size (60D) which I converted using their handy size conversion chart. It’s refreshing to see them tell me I should be wearing a 60-band despite this being a size this brand doesn’t sell, rather than giving me the nearest size they do sell or just telling me my size doesn’t exist / is out of range for their calculator. This isn’t as bad as some of the calculators below but it’s still not close to a size that would fit me. If I sister size up to a 30-band, it’d put me at a 30C which is definitely too small.


The Hilarious – Really, Really Not My Size

Victoria’s Secret – 30B

Um, no. The wording on this calculator really confused me: “Wrap a soft measuring tape around your back at band level, under each arm and around the front. Measure just above your bust, right about where the straps meet the top of the cup“. I wrapped the tape measure diagonally from band level at the back to above the bust at the front, but I’m not sure if that’s what I was supposed to do. I’m also not sure why Victoria’s Secret is asking you to measure above your bust to find your band measurement, which sits below the bust. Depending on your body shape, these could be very different measurements.

HerRoom – 30B

When I entered “the smallest measurement possible” as asked for the underbust, I was told my band size was below 30 and out of range for this calculator. However I do like my bands a tad looser than most so I plugged in an inch bigger for my underbust and got this result which is totally off.

Breast Talk – 30B

This calculator breaks if you use a fraction so I rounded my 26.5″ underbust down to 26″, but unfortunately it still didn’t give me a correct size. If I round up to 27″ underbust instead it tells me I’m a 32AA which is equally far off what fits me!


The thing that surprised me most was not how off some of these calculators were, but the fact that not one of them was spot on. Why? Because a huge amount of bra-fitting advice is dedicated to telling women that the ‘plus four’ bra sizing method is outdated or not right for everyone, and yet not one of these calculators is actually using that method (since it’s what I find works for me). Popular bra sizing methods may not be as outdated as we think.

This list isn’t meant to name and shame the bad bra fit calculators out there so much as it is meant to prove that you can’t rely on bra fit calculators alone – and especially not just one calculator – to find your size.

If you’re buying from a new brand and aren’t sure what size to go for, by all means use their calculator for guidance but take the results with a pinch of salt and remember that you’ll only really know if a bra fits you when you try it on (my ‘does my bra fit?‘ guide can help you decide!).

How many of these bra size calculators work for you? Know of any other good/bad ones I should add to my list?


The product recommendations directly above are affiliate links

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Leave a Comment


Sam December 14, 2003 - 3:45 pm

Will surely help a lot! Thanks for sharing! 😉

Reply February 16, 2008 - 7:56 am

~ i got results like 28G or 28FF?? seems rly huge. other bra calculators usually add 2 or 3 in to small band sizes. whats up with that? Rite now wearing a 32DD is fine but its not as snug as i would like should i switch or keep on buying 32s?

Estelle February 16, 2008 - 6:43 pm

Which calculators gave you those measurements out of interest?

You sound like you might be a similar size to me (I’ve changed sizes slightly since writing this post) – I often buy a 32DD because it’s an easy-to-find size, but really I prefer a more snug band so wear a 30E where available (a 30E and 32DD have the same volume in the cup – a 30DD would be smaller and probably dig in).

If you’re looking for a tighter band, a 30E the size I’d recommend trying first. If you try it and would prefer a tighter band still, then try a 28F – again, same cup volume as a 30E and 32DD.

Jeniffer December 16, 2008 - 6:33 am

A bra that fits has some useful resources and topics under their group.

One helpful topic can be

irir November 14, 2016 - 6:15 pm

Britney Spears Intimate calculator is exactly the same as Change Lingerie’s calculator, well, it is the brand that produced the collection, and they definitely have 60D.

Estelle November 14, 2017 - 1:27 pm

Ah, that may explain it. Still, I’m glad they didn’t remove the size options that don’t fit with Britney’s range, even if that was only because it would have meant more work to do so! 🙂

kitty November 14, 2025 - 1:10 pm

I wouldn’t go as far as saying that the plus four method isn’t incorrect, because adding extra inches will warp how the cup fits and how much support you’re getting from the band as opposed to the straps. It’s just that smaller bands are able to stretch less than bigger bands since there’s less material, and a smaller amount of squish around the ribcage can make even the “right” sized band feel uncomfortable. Therefore sizing up can be appropriate for smaller sizes, but isn’t automatically right for everyone.

Thanks for the informative posts, though, the world needs more correct bra information!

Kim Slawson November 14, 2025 - 4:03 pm

No love for Sizem? Try their calculator and post the results? Many have likened its accuracy to Erica’s at A Sophisticated Pair.

Also please try Treasure Linton’s “A Bra That Fits” calculator at

Inquiring minds want to know!

Estelle November 14, 2026 - 11:31 am


I’ve tried the A Bra That Fits one, it’s in this article.

I expect there may be a part 3 down the line so thanks for the Sizem recommendation.

Estelle November 14, 2026 - 11:36 am

Thanks for stopping by – I agree with you, +4 works for me but I know it doesn’t for everyone. I was just surprised that not one of these calculators is using the +4 method because there are still so many people out there saying “+4 is wrong!” but it doesn’t appear to even really be in use anymore amongst brands and retailers. I wonder if I’d tried these calculators out 5 years ago if the results would have been different…