EU to US conversion

EU 90A in US Bra Size

Convert 90A from European sizing to US sizing, with the full international table, sister sizes, and practical fit checks in one place.

Instant answer

90A (EU) =

40A US

In this sizing table, 90A in European sizing converts to 40A in US sizing.

Full conversion table for 90A (US 40A)

40A bra size conversion across US, UK, EU, French, and Australian sizing.
US	UK	EU	FR	AU
40A	40A	90A	105A	18A

Bra sizing varies between brands. Use this as an accurate starting point and check the fit.

What this conversion means

European sizing can look unfamiliar because the band and cup sequences are not always written like US labels. For 90A, this shared data file maps the fit target to 40A in US sizing.

Sister sizes for the US equivalent (40A)

Sister sizes: 38B can be worth checking when the cup volume feels close but the band needs a different feel.

What measurements make a 90A?

The useful way to read 90A is to separate the band from the cup step. In the current calculator formula, the closest starting range is about 39-41 inches (99-104 cm) under the bust and about 40.5-41.5 inches (103-105 cm) around the fullest part of the bust. The band comes from the underbust rounding, while the cup step comes from the difference between bust and band. This page uses 40A as the US equivalent for those measurement notes.

Is 90A big or small?

Whether 90A feels small, average, or full depends on the body and on the brand. In this size set, the US equivalent uses a fuller band and a lower cup step. Cup letters are relative to the band, so a D on one band is not the same volume as a D on every other band. The most useful question is whether the band stays level and the cups hold smoothly, not whether the label sounds large or small.

If 90A doesn't fit right

Band rides up: The band may be too loose or stretched out; try a snugger band or compare the snugger sister size.

Cups gape: The cup may be too roomy, too deep, or pulled away by a loose band; check the band before changing cup volume.

Cups spill: The cup volume may be too small or the cup shape may be too closed; try one cup step up before changing the band.

Straps dig in: The straps may be compensating for a band that is not supporting enough; reset the band fit before tightening straps.

How 90A differs between brands

90A can shift in feel from one retailer to another because brands grade bands and cups in their own way. A firmer elastic can make the same band feel smaller, and a shallow or narrow cup can make the same cup letter feel different. Check the retailer chart, read fit notes when available, and compare the label against the brand and region sizing guide before treating the conversion as final.

Shopping for 90A

90A is easiest to compare when you try shapes that show both cup volume and band tension clearly. If the cup is in a lower or middle step, lightly lined T-shirt styles can make gaps easy to spot. Fuller cup steps often benefit from styles with steadier side support, deeper cups, or a balconette shape depending on breast shape. For special outfits, compare the fit needs in the outfit guides before choosing a strapless, plunge, or backless option.

Bras in your size

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Everyday Fit Store

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Comfort Band Co.

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Soft Cup Edit

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FAQ

Is 90A the same as 40A in the US?

In this dataset, 90A (EU) converts to 40A in US sizing. Some brands publish their own charts, so use this as the closest standard label and still check the real fit.

What is 90A in French sizing?

90A (EU) matches the same base record as 105A (FR). The full table on this page shows each supported label side by side.

How do I check the fit of 40A?

A good US fit should feel secure without digging. If 40A feels close in the cup but wrong in the band, compare the sister sizes before changing cup volume.

What sister sizes work with 40A?

38B are the closest sister-size options for 40A in this dataset. Try a sister size when cup volume feels close but the band needs to feel snugger or looser.

Why do bra sizes differ between countries?

Bra labels are written differently across US, UK, EU, French, and Australian systems. Cup letters can also diverge after D, so a converted label is a starting point rather than a promise of identical fit.

What measurements usually make 90A?

90A maps to US 40A here. The current calculator formula points to about 39-41 inches underbust and 40.5-41.5 inches bust, or roughly 99-104 cm and 103-105 cm. Treat that as a starting range and then check the real fit.