Bra Sizes & Cup Size Chart (AA–HH) + Band & Bust Measuring Guide
Measure in minutes, confirm fit fast, and shop the right bra style for your body and your goal.
Bra sizing should feel simple: measure your band and bust, match the chart, then shop the bra type that fits your shape. This guide breaks down bra sizes, breast cup size comparisons, sister sizing, and the most common fit mistakes—so you can get a better fit on the first try.
Bra Sizes & Cup Sizes (What It Actually Means)
Your bra size is a two-part measurement: band (numbers) + cup (letters). When both are correct, bras feel supportive, flattering, and comfortable—without digging, gaping, or sliding.
Breasts vary by size, shape, density, projection, and fullness. That’s why two people can wear the same “cup letter” and look completely different. Measuring periodically matters because your size can change with weight shifts, hormones, pregnancy/postpartum, exercise, and time.
The most common reason bra shopping feels frustrating is not your body—it’s incorrect sizing. When band and cup are correct, you’ll notice:
- Better support: less shoulder strain and less bouncing.
- Better shape: tops fit smoother, lines look cleaner.
- More comfort: fewer wire marks, less spillage, less gaping.
- More confidence: your bra feels like it belongs on your body.
How to Measure Bra Sizes (Accurate in 3–5 Minutes)
Use a soft tape. Measure in inches. Keep the tape level and snug (not tight). For best accuracy, measure over a non-padded bra or bare skin.
Step 1 — Measure your underbust (band)
- Stand straight, shoulders relaxed.
- Place tape directly under your bust around your ribcage.
- Keep tape parallel to the floor and snug.
- Write down the number (inches).
Step 2 — Measure your bust (fullest point)
- Wrap tape around the fullest part of your bust (typically at nipple level).
- Keep tape level and not overly tight.
- Write down the number (inches).
How to calculate your bra size
Start with band. Then estimate cup using the difference between bust and underbust. This gets you extremely close—final fit depends on shape + style (plunge, full coverage, unlined, etc.).
Band size (quick guide)
- If your underbust is an even number, that’s a good starting band.
- If it’s an odd number, round to the nearest even number.
- If you prefer very snug support, you may choose the lower even number.
Cup size (difference method)
Example: Underbust 34" and Bust 37" → difference 3" → roughly C cup. Brands vary slightly, so confirm with the fit check section.
| Difference | Cup size |
|---|---|
| 0–½" | AA |
| ½–1" | A |
| 1–2" | B |
| 2–3" | C |
| 3–4" | D |
| 4–5" | DD / E |
| 5–6" | DDD / F |
| 6–7" | G |
| 7–8" | H |
| 8–9" | HH |
Bra Cup Sizes From AA to HH (What Each Cup Represents)
Cup letters represent volume based on the difference between bust and underbust. AA–D are often similar across systems, while DD+ can vary by brand labeling.
The goal is simple: cups fully contain breast tissue (including the sides) while the band stays stable around your ribcage. If you’re constantly adjusting straps, pulling cups up, or feeling spillage—your size or style likely needs a change.
US / UK / EU cup conversion (DD+)
Helpful reference only. Brand standards vary—prioritize your measurements + fit checks.
| USA | UK | EU |
|---|---|---|
| DD/E | DD | E |
| DDD/F | E | F |
| G | F | G |
| H | FF | H |
| I | G | I |
| J | GG | J |
| K | H | — |
| L | HH | — |
| M | J | — |
| N | JJ | — |
| O | K | — |
If your preferred brand uses a different conversion standard, adjust based on fit.
Sister Sizes (When One Part Fits, the Other Doesn’t)
Sister sizes keep cup volume similar while changing band size. This is the fastest way to dial in comfort.
The rule
If you go up a band size, go down a cup. If you go down a band size, go up a cup.
| If you wear | Band too tight? | Band too loose? |
|---|---|---|
| 34D | Try 36C | Try 32DD |
| 36C | Try 38B | Try 34D |
| 34DD | Try 36D | Try 32DDD |
| 38DD | Try 40D | Try 36DDD |
When to use sister sizing
- Band rides up: go down a band (and up a cup).
- Band feels painful: go up a band (and down a cup) or try another style.
- Cups fit, band doesn’t: sister size immediately.
- Style changes fit: plunge vs full coverage may require an adjustment.
How to Know If Your Bra Fits (Fast Checklist)
Use these signals to confirm your size and avoid the most common “almost right” mistakes.
Green flags (good fit)
- Band: level, snug on loosest hook, doesn’t ride up.
- Cups: smooth edges, no cutting in, no gaping, no wrinkling.
- Gore (wired): lies flat or close to flat.
- Straps: supportive, not digging (two fingers fit).
- Movement: lift arms/bend without shifting or spilling.
Red flags (quick fixes)
- Spillage: cup too small → go up a cup or try fuller coverage.
- Gaping: cup too big or style mismatch → go down a cup or try plunge/unlined.
- Band rides up: band too big → go down a band (and up a cup).
- Straps dig: fix band/cup first (straps shouldn’t do the heavy lifting).
Pick a style that matches your goal
- Lift/cleavage: Push-Up
- Low neckline: Plunge
- Smooth under tops: T-Shirt
- Maximum containment: Full-Figure / Full-Coverage
- Light feel: Unlined
- No-wire feel: Wireless
- High-impact support: Sports
- Smoother profile: Minimizer
Cup-by-Cup Guide (AA to HH)
What each cup typically needs: support level, best bra styles, and common fit mistakes.
AA / A Cup
AA and A cups often do best with light shaping and comfort. Try smooth T-shirt bras for clean lines, or unlined bras for a natural feel.
B Cup
B cups are versatile across styles. For everyday, choose T-shirt bras; for lower necklines, plunge; for activity, sports bras.
C Cup
C cups can feel different depending on fullness and projection. If you gap on top, try plunge or unlined. For smooth shape, choose a supportive T-shirt bra.
D Cup
D cup is where structure matters more: a stable band and supportive cups make a big difference. Full coverage helps containment; plunge helps neckline without cutting in.
DD / E Cup
DD/E is extremely common—and commonly mis-sized. If you spill or straps dig, you may need a smaller band and larger cup, or a more supportive style.
DDD / F, G, H, HH Cups
DD+ typically feels best with firmer bands, supportive wings, and cups that contain side tissue. For a smoother profile, consider minimizers; for activity, choose sports bras built for containment.
Shop Bras by Need (Fast Picks)
If you don’t want to overthink, start with your goal. These options solve the most common fit problems quickly.
Everyday & essential bras
Support & shaping
Sexy + specialty
Bra Size FAQ (Fast Answers)
The questions people ask right before they buy (also helps reduce returns).
What if I’m between two band sizes?
Start with the band that feels stable on the loosest hook without riding up. If you prefer snug support, choose the smaller band. If you want a softer feel, choose the larger band—then adjust cup using sister sizing.
What if I’m between two cup sizes?
If you have spillage or cutting in, go up a cup. If you have gaping or wrinkling, go down a cup or try a different style (plunge and unlined often solve gaping).
Why do my straps dig into my shoulders?
Usually a band/cup issue. If the band is too loose, straps take on too much weight. Try a smaller band (and larger cup via sister sizing) or choose a more supportive style like Full-Figure bras.
What bra style is best for DD+?
Start with DD+ bras and Full-Figure/Full-Coverage for containment. For a smoother profile under clothing, consider minimizers. For a lighter feel, try unlined bras built with strong support.
Quick shop: DD+ Bras Full-Figure Minimizer
Should sports bras be tighter?
They should reduce bounce without restricting breathing. If you feel pain or numbness, it’s too tight or the style isn’t right for your body.
Quick shop: Sports Bras
How often should I re-measure my bra size?
Every 6–12 months, and any time your body changes (weight shifts, pregnancy/postpartum, new workout routine, or if your bras suddenly feel “off”).
Where do I start if I don’t know my bra size at all?
Measure underbust and bust, use the difference chart to estimate cup, then confirm with fit checks. The easiest starting point is a T-shirt bra—or Full-Figure for DD+ comfort.
Quick shop: T-Shirt Bras Full-Figure
Disclaimer: Sizing can vary by brand, fabric, and design. Use measurements as a starting point and confirm with fit checks. When a product page includes a specific sizing note, follow that first.
Ready to Shop the Right Fit?
Use your measurements as your foundation, then choose the style that matches your goal.