How to Measure for a Calvin Klein Bra Size
Two measurements, under 3 minutes. Get your exact Calvin Klein size across the 30A–38DD range, plus how to pick S/M/L for Modern Cotton bralettes — no store visit needed.
Verified Jun 2026 · Source: Calvin Klein official size guide ↗
Calvin Klein Bra Size Calculator
Enter your band and bust measurements — we'll show your CK 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 Calvin Klein 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. Keep the tape level and parallel to the floor all the way around. Round to the nearest whole inch.
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 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 is one cup size: 1 inch = A, 2 = B, 3 = C, 4 = D, 5 = DD. Calvin Klein uses standard US cup notation.
Tip: Example: 37-inch bust minus 34-inch band = 3 inches = C cup.
Combine to get your Calvin Klein size
Your CK size is your band number plus your cup letter — a 34-inch band with a 3-inch difference is a 34C. Calvin Klein's band/cup range runs 30A through 38DD. For Modern Cotton bralettes, switch to S/M/L instead: S fits roughly 32A–34B, M fits 34B–36C, L fits 36C–38D.
Tip: Use the calculator above to confirm your size and see it in US, UK, and EU 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 (34C → 32D) for a tighter band, or up one band and down one cup (34C → 36B) 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 Calvin Klein Bras Run True to Size?
In underwire and lined styles, Calvin Klein runs true to standard US sizing — the size you calculate above is typically the right pick, and a CK band matches the same band number in other standard-US brands. The exception is the Modern Cotton bralette line, which uses S/M/L and runs slightly small; most women find sizing up gives a more comfortable fit. CK's cups are moderately shaped with less padding than push-up brands, so the same size can feel a little more natural and less structured.
Picking the Right Calvin Klein Bra in Your Size
| Style | Sizing | Note |
|---|---|---|
| Perfectly Fit / underwire | Band + cup | True to size |
| Modern Cotton bralette | S / M / L | Runs slightly small — size up if between |
| CK One lightly lined | Band + cup | Natural shape, light lining — true to size |
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 (34C → 36B). Cup overflowing? Go down a band and up a cup (34C → 32D). Both fit the same amount of tissue.
Next steps
Got your size? Compare it against Calvin Klein'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: