The size of a bra is based on two distinct measurements: the underbust measurement (under the bust) and the bust measurement (at the fullest point). The combination of these two figures determines both the band size (80, 85, 90, etc.) and the cup letter (A, B, C, D…). At Etam, this logic remains the same, but some grid and shape peculiarities complicate the conversion.
Underbust and bust measurements: two measurements, two distinct roles
The underbust measurement is taken horizontally, just under the bust, with a tape measure flat against the skin. This number in centimeters gives the band size: a measurement of 73 cm generally corresponds to an 85, while a measurement of 78 cm points to a 90.
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The bust measurement is taken at the fullest point of the bust, without compressing. The difference between these two measurements determines the cup size. Each gap of about 2.5 cm moves you from one letter to the next: a gap of 15 cm gives an A cup, 17.5 cm a B cup, and 20 cm a C cup.
To calculate your bra size at Etam, these two measurements remain the starting point, but the in-house grid may slightly shift the correspondences compared to other brands.
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Etam grid and EPAP guide: why correspondences vary
Etam offers two distinct size charts online. The first, intended for the French market, associates each range of centimeters with a classic band size. The second, called the EPAP guide (Europe, Portugal, Africa), uses slightly different thresholds.
In practice, a customer whose underbust measurement falls at 78 or 79 cm may be directed to a 90 on the French guide, but be on the 85/90 border on the EPAP chart. Choosing the wrong reference can shift the size by one notch. Before ordering online, checking which guide is displayed (the URL of the size page specifies this) helps avoid a common mistake.
Sister sizes: an often-overlooked adjustment
The concept of sister sizing involves compensating for a band that is too tight or too loose by simultaneously adjusting the cup letter. A 90B offers a cup volume similar to an 85C or a 95A. The band changes, but the overall volume remains comparable.
Etam has begun to incorporate this principle into its fitting advice. If a specific model is tight at the band without the cup overflowing, going down a band size while going up a cup letter may be enough to correct the issue, without changing the range.
Etam shapes and size recalculation by model
The cup depth is not the same from one model to another. Etam has expanded certain depths across several shapes (push-up, scarf, thin cups) in its recent collections. As a result, a customer used to a 90C in an old collection may be advised to try a 90B or a 90D depending on the shape chosen in the current models.
The conversion from old size to new shape is no longer strictly equivalent. This shift does not mean that the body shape has changed, but that the bra pattern has evolved. Recalculating your size with the current chart, rather than relying on a size purchased two or three years ago, remains the most reliable precaution.
Check the fit in three points
Once the model is on, three areas help confirm that the size works:
- The band: it should remain horizontal, without riding up the back. If it rides up, the band size is too large or the straps are pulling too much.
- The cup: no empty wrinkles at the top of the breast (cup too large) or overflow at the sides (cup too small). The breast should fill the cup without distorting it.
- The center gore: the small band between the two cups should lie flat against the sternum. If it floats, the cup lacks depth or the band is too loose.
Straps and hooks: adjustments that skew the size diagnosis
A new bra closes on the loosest hook row (the furthest from the edge). The following rows are used to compensate for the elasticity that relaxes with washing. Closing a new model on the last hook means that the band is already too large, even if it feels correct at the time of fitting.
The straps ensure positioning, not support. If the weight of the bust rests on the shoulders rather than on the band, the band size is likely undersized. Shortening the straps does not compensate for a band that is too loose: it simply raises the underwires, which end up digging in under the arms.
Frequency of checking
The bust evolves with weight fluctuations, hormonal cycles, and tissue aging. Taking measurements once or twice a year, or with each notable body change, allows for size adjustments before purchasing a model out of habit.
At Etam, the fitting service in-store offers a quick measurement. Some stores also have a scanning tool that refines the recommendation. These options are more reliable than an estimation at home with a poorly positioned tape measure.
The size listed on the label of an old bra is not a definitive reference. Between the evolution of size charts, differences in shape, and wear of the worn model, only a recent measurement associated with the correct chart guarantees a proper fit.