What Is Sister Sizing?

Sister sizing is the bra industry's method for swapping between adjacent band and cup sizes while keeping the same cup volume. The rule is simple: when you move one band size down, move one cup letter up — and vice versa. For example, 34B, 32C, and 36A all hold roughly the same cup volume, just on different band lengths.

Why does this matter? Because every brand fits slightly differently, and even your own body changes through the month. Knowing your sister sizes gives you instant alternatives when a bra fits well in the cup but the band is too tight or too loose. At AngelofYou, our combination cup sizing (AB, CD, EF) makes sister sizing even easier — one size covers two traditional cup letters.

The Sister Sizing Chart: 32AB / 34AB / 36AB Explained

Here is the quick-reference sister sizing chart most women need. Find your usual size on the left, then read across for the sisters that hold the same cup volume:

Band 32 (small frame): 32AB ↔ 30C ↔ 34A
Band 34 (average frame): 34AB ↔ 32C ↔ 36A
Band 36 (fuller frame): 36AB ↔ 34C ↔ 38A
Band 38 (plus frame): 38AB ↔ 36C ↔ 40A
Band 40+: 40AB ↔ 38C ↔ 42A

For AngelofYou's combination sizing, treat AB as covering both A and B cups, CD as covering C and D, and EF as covering E and F. That means if you traditionally wear 34B, you can confidently choose 34AB — and if the band runs snug, 36AB is your comfortable sister.

When to Size Up or Down (and Which Sister to Pick)

Choose a smaller band sister (e.g., 36AB → 34CD) when: your bra rides up your back, the band feels loose on the loosest hook, or the straps do all the work. A snugger band carries about 80% of breast weight and is the single biggest fit improvement you can make.

Choose a larger band sister (e.g., 34AB → 36AB) when: the band digs into your ribs, leaves red marks, or you're between sizes and the bra is new (elastic relaxes after a few wears).

Choose the same band, different cup (e.g., 34AB → 34CD) when: the cup spills over the top or sides, or you see gaping at the top of the cup. Cup fit issues are volume issues — fix the letter, not the band.

How to Measure Yourself at Home (2 Minutes)

Step 1 — Band: wrap a measuring tape snugly around your ribcage, directly under your bust. Keep it level and parallel to the floor. Round to the nearest even number — that's your band size.

Step 2 — Bust: measure around the fullest part of your bust, keeping the tape level. The difference between bust and band measurement maps to your cup letter (1 inch = A, 2 = B, 3 = C, 4 = D).

Step 3 — Match to AngelofYou: combine the band number with your letter range. 32-inch band with 2-inch difference = 32AB; 34-inch band with 3-inch difference = 34CD.

Real-World Sister Sizing Examples

Still unsure? Here are three common scenarios our customers write in about:

"My 34B feels perfect in the cup but the band rides up." → Try 32CD. Same volume, tighter band, better support.

"I'm between 36 and 38 and the 36 band leaves marks." → Try 38AB, and if the cups feel loose, step down to 36CD first — that's the volume-preserving move.

"The bra I love only comes in AB and I wear a C." → Try the AB with the next band up. 34C ≈ 36AB in volume, so the fit usually lands within a hook or two.

AngelofYou Sizing Notes

Every AngelofYou bra ships in combination sizes (32AB-38AB, 32CD-38CD, and EF where available), which streamlines sister sizing to a two-step move: keep volume, adjust band. Our padded push-up and contour styles fit true to the chart above; our unlined drawstring style is the most forgiving if you're between sizes, thanks to its adjustable drawstring.

Not sure between two sizes? Order both, keep the better one — every order includes FREE SHIPPING ON EVERY ORDER and a 30-day easy return window.

Sister Sizing FAQ

Is sister sizing the same as "true to size"? No. True-to-size means the bra matches the size on the label; sister sizing is about finding the best fit by shifting band and cup together.

Can I sister size more than one step? Technically yes (34B → 30D), but we recommend a maximum of one band step for the best support and shape.

Do sister sizes look the same? The cup volume is similar, but the silhouette changes slightly — a smaller band with a bigger cup gives more lift, while a larger band with a smaller cup gives a softer, more natural shape.

What if I'm between two AngelofYou sizes? Choose the smaller band if your current bras ride up; choose the larger band if they leave marks. Both ship free with easy returns, so trial-and-error costs nothing.

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