Plus Size Bra Sizing Guide | Measure, Convert, Repeat

Plus size bra sizing starts with two measurements: snug underbust for band, fullest bust for cup, then subtract band from bust.

For the full breakdown, see our best Bra For Plus Size Women guide.

Most US plus size bra sizing follows the same two-tape method: one measurement around the ribcage, one across the fullest part of the bust, and a simple subtraction to land on a cup letter. The catch is that one brand’s 42DD is not always another brand’s 42DD, so the numbers get you close, and a fitting room gets you exact.

How To Measure For A Plus Size Bra

Take both measurements in front of a mirror, wearing a lightly lined, unpadded bra if you have one. Skip push-up bras, minimizers, and sports bras — padding shifts both the band and bust readings.

Wrap the tape snugly around your ribcage, directly under your breasts. Keep it level all the way around; a tilted tape adds or subtracts inches you don’t actually have. This number is your band size. If it lands on an odd number, round up to the nearest even —

Move the tape up to the fullest part of your bust, keeping it parallel to the floor. Subtract the band measurement from the bust measurement. The difference maps to a cup letter:

If you fall between two sizes, round up on both band and cup.

How Do Plus Size Bra Charts Differ By Region?

US brands like Lane Bryant and Calvin Klein size in inches and use conventional US band and cup letters. That changes once you cross the Atlantic. Yours Clothing, a UK plus size retailer, publishes a plus size bra chart covering bands from 36 to 60 UK, with EU sizes from 80 to 140 and FR/ES/BELG sizes from 95 to 155.

Shop with the chart from the specific brand you are buying. But the conversion is not universal across all manufacturers, so a chart is a starting point, not a law.

Common Fitting Mistakes That Throw Off Your Size

The most common error is measuring over a bulky or padded bra. A push-up bra adds up to two cup sizes of fake reading, and a thick sports bra compresses the band. The second is a tilted tape — it adds circumference on one side and subtracts it on the other, and you end up ordering the wrong size entirely. The third is pulling the tape too tight. Several guides say snug, not tight, and the distinction is real: a vice-grip band measurement lands you in a band that cuts into your ribs all day. For larger breasts, Good Housekeeping notes that measuring in an unlined, non-padded bra rather than a sports bra is the right call, since the tape needs a natural silhouette to measure.

What Does A Correctly Fitted Plus Size Bra Feel Like?

A proper fit has four checkpoints. The band sits level across your back, not riding up. The center gore — the flat piece between the cups — lies flat against your sternum. The underwire, if present, follows your breast root rather than digging into tissue. And the straps carry maybe 10% of the weight; the band should do the heavy lifting.

If your current bra rides up in back, the band is too loose. If the straps dig in, the band is likely too big and compensating. If you spill over the top or sides, the cup is too small. Any one of these signs means remeasuring and trying a different combination of band and cup — often one band size down and one cup size up from what you are wearing.