How to Measure for a Wacoal Bra Size
Two measurements, under 3 minutes. Get your exact Wacoal size across their full range — bands 30–46 and cups up to K — no store visit needed.
Verified Jun 2026 · Source: Wacoal America official fit calculator ↗
Wacoal Bra Size Calculator
Enter your band and bust measurements — we'll show your Wacoal size instantly, with sister sizes.
Measure snugly around your ribcage (underbust) and at the fullest part of your bust.
Where to place the tape
Band sits level around your rib cage just under the bust. Bust wraps the fullest point.
Measure your bust
Wrap a tape around the fullest part of your bust. Keep it level and not too tight.
Measure your underbust
Wrap the tape snugly around your ribcage, just below your breasts. Keep it level.
Enter your measurements
Use our calculator to get your size in US, UK, EU, and AU systems with sister sizes.
How to Measure for a Wacoal Bra: Step by Step
Wear a non-padded bra
Put on a regular T-shirt bra or unlined bralette — not a push-up, sports bra, or minimizer. Padded styles add volume and skew your bust measurement.
Tip: If you can see the shape of your natural bust in the mirror, you're ready to measure.
Measure your band (underbust)
Wrap a soft tape measure snugly around your rib cage directly under your bust, level all the way around. Wacoal’s own fit calculator uses your underbust measurement directly — no inches added — and tells you to round up to the next whole number if you land on a fraction.
Tip: The tape should feel firm but not tight — you should be able to breathe normally.
Measure your bust
Wrap the tape around the fullest part of your bust. Keep it level but relaxed — not pulled tight, not loose. Round up to the nearest whole inch.
Tip: Look in a mirror from the side to confirm the tape isn't dipping or riding up.
Calculate your cup size
Subtract your band measurement from your bust measurement. Each inch of difference equals one cup size: 1 inch = A, 2 = B, 3 = C, 4 = D, 5 = DD, 6 = DDD, 7 = G, and up from there.
Tip: Example: 39-inch bust minus 34-inch band = 5 inches = DD cup.
Combine to get your Wacoal size
Your Wacoal size is your band number plus your cup letter. Wacoal carries bands 30–46 and cups A through I on its everyday lines, with the full-figure collection extending all the way to a K cup — one of the widest ranges of any mainstream brand.
Tip: Use the calculator above to double-check and see your size in US, UK, EU, and AU systems.
Verify with sister sizes if the fit feels off
If your calculated size doesn’t feel right, try a sister size: go down one band and up one cup (36D → 34DD) for a tighter band, or up one band and down one cup (36D → 38C) for more room. The cup volume stays the same.
Tip: Both directions hold the same amount of breast tissue — only the band fit changes.
Do Wacoal Bras Run True to Size?
Yes — Wacoal runs true to size and is known for accurate, supportive fits, especially in fuller cups. Structured and underwire styles like the How Perfect Wire-Free fit as measured. The one style to watch is the Basic Beauty Seamless: its molded fabric runs small, so order one band and one cup up. Minimizer styles reduce projection by about an inch rather than changing your size — stay with your measured size and let the design do the work.
Picking the Right Wacoal Bra in Your Size
| Style | Best for | Sizing note |
|---|---|---|
| How Perfect Wire-Free | Everyday comfort | True to size |
| Basic Beauty Seamless | Smooth under clothes | Runs small — order one band and cup up |
| Visual Effects Minimizer | Reducing projection | Stay true to size; reduces ~1 inch of projection |
What If Your Size Doesn't Fit?
Bra fit is rarely about a single number — if your measured size feels off, you probably need a sister size, not a different measurement. Sister sizes share cup volume but shift the band. Band too tight? Go up a band and down a cup (36D → 38C). Cup overflowing? Go down a band and up a cup (36D → 34DD). Both fit the same amount of tissue.
Next steps
Got your size? Compare it against Wacoal's full chart, or check the fit checklist to make sure your bra is working as hard as you are.
Also see: how a well-fitting bra should feel · signs you're wearing the wrong bra size · bra fit troubleshooter
Measuring for another brand?
The band-and-bust method is the same across brands — only the size range and style notes differ. Brand-specific measuring guides: