Ever wondered what your bra size is or felt confused about how to measure to find it? This blog details how to find your bra size accurately at home! Read on to discover how to find the best bra fit for you.
What to Keep in Mind
Your bra size is made up of two measurements:
Band size: the number, such as 30, 32, 34, 36, 38, 40, and so on
Cup size: the letter, such as A, B, C, D, E, or F
The important thing to remember is that cup size depends on band size. A 34C does not have the same cup volume as a 36C.
Your bra size can also vary slightly between brands and styles, so think of your measurement as a starting point rather than your size with every brand.
Bra Measurement Calculator
If you want to find your bra size, here’s a simple way to estimate your starting bra size at home.
Step 1: Measure Your Band
Using a soft measuring tape, measure snugly around your rib cage directly beneath your bust.
Most bra brands use even-numbered band sizes, you’ll typically round to the nearest even number.
Examples:
| Underbust Measurement | Starting Band Size |
| 31–32 in. | 32 |
| 32.5–34 in. | 34 |
| 34.25–36 in. | 36 |
| 36.25–38 in. | 38 |
Step 2: Measure Your Bust
Measure around the fullest part of your bust while standing naturally.
Example:
- Bust = 37 inches
Step 3: Calculate Your Cup Size
Subtract your band measurement from your bust measurement.
| Difference | Estimated Cup Size |
| 1 inch | A |
| 2 inches | B |
| 3 inches | C |
| 4 inches | D |
| 5 inches | DD / E |
| 6 inches | DDD / F |
| 7 inches | G |
Example:
- Bust: 37 inches
- Band: 34 inches
- Difference: 3 inches
- Estimated bra size: 34C
This gives you a strong starting point before heading to the store to try on bras. Keep in mind that different brands, fabrics, and bra styles can fit differently, so your best size may vary slightly.
Signs Your Band May Be Too Big
Your band may be too large if:
- it rides up your back
- you can easily pull it several inches away from your body
- your straps are doing most of the supporting
- you immediately need to use the tightest hook
- the bra shifts when you move
If the cups fit correctly but the band feels loose, try going down a band size and up a cup size to maintain similar cup volume. For example, you might try a 34D instead of a 36C, these are known as sister sizes.
Signs Your Band May Be Too Small
Your band may be too small if:
- it feels painfully restrictive
- it leaves excessive marks
- you struggle to fasten it comfortably
- the underwire feels compressed against your rib cage
Before sizing up, check the cups too. Cups that are too small can sometimes make the entire bra feel tighter because the breast tissue does not have enough room. If the cups fit but the band is genuinely too tight, try going up a band size and down a cup size to maintain similar cup volume.
Signs Your Cups May Be Too Small
Consider sizing up in the cup if:
- you spill over the top or sides
- the center of the bra does not sit flat against your chest
- the underwire rests on breast tissue
- you experience noticeable bulging around the cups
The right cup should comfortably contain your breast tissue without cutting into it.
Signs Your Cups May Be Too Big
Your cups may be too large if:
- there is significant gaping
- the fabric wrinkles
- the cup feels noticeably empty in certain areas
However, gaping does not always mean you need a smaller cup.
Different bra shapes work for different breast shapes. If the band and cup volume seem correct but the bra still gaps, the style itself may simply not be the right match for you.
When to Size Up or Size Down
Bra sizing becomes easier when you identify exactly where the fit problem is.
Band too loose, cups fit: Go down a band and up a cup.
Band too tight, cups fit: Go up a band and down a cup.
Band fits, cups overflow: Go up a cup.
Band fits, cups gap: Try a smaller cup or a different bra shape.
Instead of assuming the entire bra is the wrong size, look at the band and cups separately.
When You Want More Than General Advice
The right undergarments create the foundation for how clothing fits and falls on the body. If your wardrobe still feels difficult to navigate even when you understand your proportions, Abby Young Styling helps clients understand the bigger picture through personalized styling, Silhouette Analysis, and wardrobe support.
You can learn more about our styling services here.
If you’re looking for more help to find the perfect bra, please contact Susan Testa. Susan is the owner of Romantiques and French Lessons boutiques in Los Gatos.
Susan has been an expert in bra fitter for 20 years. You can schedule a fitting with Susan here and you will be in great hands.
Romantiques & French Lessons offers a curated collection of clothing, loungewear, lingerie, jewelry, beauty, and more.
Continue Reading
If this topic resonated, you may also enjoy Spring Staples for Inverted Triangle Body Shape, which explores how understanding your proportions can make choosing clothing and creating balanced outfits easier.
