If you ever stand in the bra section, staring at the tags like 32B or 36DD and wondering what it all really means, you are not alone. Bra sizing can feel like a secret code, and it's been confusing women for decades. Once you understand the secret, it's very straightforward. So, let's unravel the mystery of what those numbers and alphabets (A, B, C, D) represent, why those alphabets matter, and the surprising truth about how they play a significant role in getting a correct fit.
Table of Contents
Bra Size Numbers and Letters Explained
How to Measure and Calculate It Yourself
House of Zelena Size Chart (Inches)
Difference Between Cup Size and Bra Size
Sister Size Benefits and Limitations
Why Size Chart Alone is Not Enough for Pregnancy/nursing
Maternity & Nursing Size Adjustment Guide
Bra Size Numbers and Letters Explained
Many people think cup size is a fixed size, but it is not. Cup size is based on measurements, not on how the breast looks. Cup size depends on the difference between two measurements on your body.
Band Size: The number is your band size, measured around the ribcage under your bust. It is usually an even number like 28, 30, 32 (in inches for US/UK sizing). This measurement is the foundation of your bra size, because the band provides about 80 to 90% of the support, not the straps. The band should feel firm but comfortable without riding up.
Bust Size: The bust size is measured around the fullest part of your breasts. Now the important part; the difference in inches between the bust size and the band size decides the cup letter. The cup letters (A, B, C, D, etc.) are just names for how big that difference is.
How to Measure and Calculate It Yourself
Step 1: Measure your Band Size
Stand straight, exhale and wrap a measuring tape gently (not tightly) around your ribcage, right under your breasts where the bra band would sit. Keep the tape level parallel to the floor. Round the measurement to the nearest whole number.
Step 2: Measure your Bust Size
Wrap the measuring tape loosely around the fullest part of your breasts (usually at the nipple level). Don't pull the tape tight, let it gently wrap your body naturally.
Step 3: Subtract Band from Bust
Now, take the bust measurement minus the band measurement (not the other way around) = the difference in inches. The difference between these two measurements tells you the cup letter.
House of Zelena Size Chart (Inches)
To ensure the best fit, comfort, and support, we strongly recommend choosing your size using House of Zelena’s brand size chart.
Remember: Always measure yourself and refer to our brand size chart before ordering to get the most accurate size and an ideal fit experience.
Difference Between Cup Size and Bra Size
People often confuse these measurements, they are two parts of the same puzzle.
Bra Size: The bra size is the full size like 32C, it combines the band size (the number 32), your underbust/ribcage measurement in inches and the cup size in letters (alphabet C), how much your bust projects beyond the band.
Cup Size: Cup size is just the letter part. It measures the difference between your bust and band measurement. It is all about the volume.
What Are Sister Bra Sizes
Sister bra sizes are alternative bra sizes that hold the same cup volume but with different band sizes. They are called sister sizes because they are close but not identical.
The rule is simple:
Go up one band size, go down one cup letter (e.g., 34D → 36C).
Go down one band size, go up one cup letter (e.g., 34D → 32DD).
Sister Size Benefits and Limitations
Sister bra size gives you more options when choosing a bra. They help when your exact size is unavailable, when you need adjustment, like going up a band or down a band size if the band feels tight.
| Positives of Sister Sizes | Negatives of Sister Sizes |
|---|---|
| More options if your exact size is sold out | Looser band can give less support |
| Helps adjust fit across different brands | Band may ride up if too loose |
| Same cup volume with band change | Cup shape can change slightly |
| Improves comfort if band feels tight | Wider bands spread volume more |
| Useful during body changes (pregnancy, bloating) | Narrower bands give more forward shape |
| Great for hard-to-find sizes | Wire and strap placement may feel different |
| Easy size adjustment without re-measuring | Not an exact fit replacement |
Why Size Chart Alone is Not Enough for Pregnancy/nursing :
A regular size chart can never truly understand the journey of pregnancy and nursing. Mothers body is constantly changing, growing and adapting in ways that numbers on charts simply cannot capture.
Key reasons include:
- Ribcage expands in pregnancy: As the baby grows, the ribcage gradually expands, affecting band comfort.
- Breast volume fluctuates daily: Breast size can change from morning to night due to fluid retention or milk flow.
- Postpartum swelling: After delivery, temporary swelling can distort measurements and alter the cup fit.
- Comfort tolerance is lower: Skin sensitivity and tenderness increase, making precise comfort more important than numbers alone.
Maternity & Nursing Size Adjustment Guide
During pregnancy and nursing, your body changes continuously, so bra sizing needs to adapt at each stage. Here’s a simple guide to adjusting your band size:
- Early Pregnancy: No adjustment is needed. Your pre-pregnancy band size will still fit comfortably as the changes are minimal at this stage.
- Mid Pregnancy: Add 1 inch to your band size. This adjustment is not just for your current comfort level, it anticipates future growth.
- Late Pregnancy: Add 1 - 2 inches to your band size, depending on comfort and body changes.
- Early Nursing: Use the band size from late pregnancy. Your body is still adjusting, and this size continues to provide the support you need.
- After 8 Weeks of Nursing: Re-measure your band and cup size, as your body may have settled or adjusted postpartum.
Maternity & Nursing Cup Size Adjustment
During pregnancy and nursing, your breasts can change rapidly sometimes from day to day. Adjusting your cup size ensures comfort, proper support, and prevents pressure on tender or engorged breasts. Here’s a simple guide:
- When breasts feel full or tender: Add +1 to your current cup size. This small adjustment accommodates temporary swelling, giving your breasts space to feel comfortable without restriction.
- When milk is established or breasts are engorged: Add +2 cups. Once milk production is fully underway, your breasts may feel heavier and firmer. Increasing the cup size ensures your bra supports the added volume, prevents discomfort, and helps with the pressure points.
By making these small cup size adjustments alongside band adjustments, your bras can adapt to the natural fluctuations of pregnancy and nursing, keeping you comfortable and supported every step of the way.
Why Is It Important to Wear the Right Bra Size?
Wearing the correct bra size is not just for looks; it is also about health and comfort.
Key benefits of the right fit:
1. Better posture and reduced back/shoulder/neck pain.
2. Prevents digging straps, red marks, or spilling over.
3. Improves breast support, reducing sagging over time.
4. Boosts confidence and how clothes fit.
5. Avoids skin irritation & breathing restrictions.
Bra sizes are simple once you know the basics. The right band and cup size together give better support, comfort, and confidence. For a smooth online bra shopping experience, explore House of Zelena’s collection of comfortable maternity bras, available with a detailed sizing guide, so you can find your perfect fit.