US to FR conversion

38D in French Bra Size

Convert 38D from US sizing to French sizing, with the full international table, nearby sister sizes, and fit checks in one place.

Instant answer

38D (US) =

100D FR

In this sizing table, 38D in US sizing converts to 100D in French sizing.

Sizing varies by brand

A conversion gives you the closest label in another sizing system, but brands can grade cups, wires, and bands differently. Use the converted size as a starting point, then check the retailer's chart and the fit of the actual bra.

Before you buy in French sizing

Use 100D as the translated label, not as a fit guarantee.
Check the retailer's size chart because some brands grade bands and cups differently.
If the cup volume feels close but the band changes, compare sister sizes before switching cup letters.
When possible, check return rules before buying across sizing systems.

Full conversion table for 38D

38D bra size conversion across US, UK, EU, French, and Australian sizing.
US	UK	EU	FR	AU
38D	38D	85D	100D	16D

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

Sizes near 38D in French sizing

If 38D is close but not right, these are the neighbouring US sizes and what each one becomes in French sizing. Band neighbours change the fit around the ribcage; cup neighbours change volume.

US sizes adjacent to 38D and their French equivalents.
US size	FR size	How it differs
36D	95D	One band step snugger, same cup letter.
40D	105D	One band step looser, same cup letter.
38C	100C	One cup step down, same band.
38DD	100E	One cup step up, same band.

What this conversion means

For 38D, the band stays tied to the 38 US band while the label is translated into French sizing. In this dataset, 38D (US) converts to 100D (FR). Treat that as the starting label, then check the brand chart and the real fit.

Sister sizes for 38D

Sister sizes: 36DD and 40C can be worth checking when the cup volume feels close but the band needs a different feel.

What measurements make a 38D?

38D is built from a band measurement and a bust measurement, not from the label alone. In the current calculator formula, the closest starting range is about 37-39 inches (94-99 cm) under the bust and about 41.5-42.5 inches (105-108 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.

Is 38D big or small?

38D is not automatically big or small; it depends on the band and the cup together. In this size set, the US equivalent uses a fuller band and a middle 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 38D 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 38D differs between brands

Two brands can print 38D or its equivalent on the tag and still cut the bra differently. 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 38D

When shopping for 38D, start with styles that make the band easy to judge. 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

Looking for 38D? We may earn a commission if you buy through sponsored links.

Everyday Fit Store

Placeholder for a broad size range and return-friendly basics.

→

Comfort Band Co.

Placeholder for supportive everyday styles by band and cup.

→

Soft Cup Edit

Placeholder for wire-free and lounge options.

→

FAQ

Is 38D in the US the same as French sizing?

Use 100D as the French match for 38D in this dataset. The label may look similar in some systems, but it still belongs to a different sizing sequence.

What is 38D in Australian sizing?

In this same table, 38D converts to 16D (AU). That helps when a retailer shows a Australian chart instead of a French one.

How do I know if 38D fits?

A good fit should feel secure without digging. Watch for a band that rides up, cups that wrinkle, or straps carrying most of the support.

What sister sizes work with 38D?

36DD and 40C are the closest sister-size options for 38D 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?

Countries and brands do not all use the same band labels or cup-letter sequence. A conversion translates the closest standard label, but the final fit still depends on the specific bra.

What measurements usually make 38D?

The current calculator formula points to about 37-39 inches underbust and 41.5-42.5 inches bust, or roughly 94-99 cm and 105-108 cm. Treat that as a starting range and then check the real fit.