Complete Bra Size Guide
A Cup to D Cup: The Complete Bra Size Guide
Everything you need to measure yourself accurately, interpret the size chart, and find your perfect fit
Understanding your bra size is one of the most impactful things you can do for your daily comfort. Yet most women are wearing the wrong size — studies suggest up to 80% of women wear a bra that's not the right fit. The good news? Getting it right is simpler than you think.
1 How Bra Sizing Actually Works
Bra sizes are expressed as a band number + cup letter — for example, 34C.
- The number (34) is your underbust measurement — the circumference of your rib cage just under your breasts, rounded to the nearest whole inch.
- The letter (C) is your cup size — the difference between your bust measurement (across the fullest part of your breasts) and your underbust measurement.
The larger the difference, the larger the cup letter. An A cup = 1 inch difference. B = 2 inches. C = 3 inches. D = 4 inches.
2 Step-by-Step: How to Measure Yourself
What you'll need: A soft measuring tape · An unpadded bra (or no bra) · A mirror · Pen and paper
Measure Your Underbust
Wrap the tape measure around your torso directly under your breasts. Keep it parallel to the floor. The tape should be snug but not tight. Round to the nearest whole inch — this is your band size.
Example: If your underbust measures 31.5 inches, your band size is 32.
Measure Your Bust
Keeping the tape parallel, measure around the fullest part of your breasts — typically at nipple level. Don't pull the tape tight; let it rest naturally. Round to the nearest whole inch.
Example: If your bust measures 38 inches, your bust measurement is 38.
Calculate Your Cup Size
Subtract your underbust from your bust measurement:
38 (bust) − 32 (band) = 6" difference → Your size is 32D
| Difference (inches) | Cup Size |
|---|---|
| 1" | A |
| 2" | B |
| 3" | C |
| 4" | D |
| 5"+ | DD / E |
3 Common Bra Sizing Mistakes — And How to Avoid Them
- Assuming your size is static. Measure at least once a year or after any major body changes.
- Adding inches to the band. The outdated "add 4–5 inches" method leads to a too-loose band and too-small cups.
- Only shopping by cup letter. A D cup from one brand fits differently in another. Always check the brand's specific size chart.
- Ignoring band comfort. The band carries 80% of the support. If it feels tight on the loosest hooks, size up the band and down the cup.
4 How to Read a Bra Size Chart
Here's a general reference for US sizing (always check the specific brand's chart):
| Underbust | 30" | 32" | 34" | 36" | 38" | 40" |
|---|---|---|---|---|---|---|
| Bust 34" | 30C | 32B | 34A | — | — | — |
| Bust 36" | 30D | 32C | 34B | 36A | — | — |
| Bust 38" | 30DD | 32D | 34C | 36B | 38A | — |
| Bust 40" | — | 32DD | 34D | 36C | 38B | 40A |
| Bust 42" | — | — | 34DD | 36D | 38C | 40B |
Note: Sizing varies between brands. Always check the specific brand's chart.
5 Signs Your Size Is Wrong
🚩 Red Flags — Your Size May Be Off
6 Finding the Right Bra for Your Size at LilyCurve
LilyCurve offers a full range of sizes from 32A to 44D, with bras specifically designed for each body type:
- Fuller cups (C–D): Our Jelly Smoothing and Full Coverage styles offer superior shape without uncomfortable squeeze.
- Smaller bands (30–32): Look for wireless options that provide lift without underwire.
- Larger bands (38+): Wide straps and back-smoothing bands prevent rolling and digging.
Take the LilyCurve Fit Quiz
Find your perfect fit in 2 minutes — no measuring tape required.
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