Did you know that 80% of women in India wear the wrong size bra? 70% of them wear bras that are too small, and 10% wear bras that are too big. Wearing the wrong size can lead to back pain, poor posture, and discomfort. Most of us have experienced the discomfort of a tight band, loose cups or digging straps—but few realise that the culprit is often a lack of understanding about two essential measurements: underbust and overbust.
What Is Underbust and Overbust? When you’re armed with the knowledge of what these terms mean and how to measure them properly, you’re on the path to achieving that elusive perfect fit.
What Is an Underbust?
Your underbust refers to the circumference of your ribcage just below your bust, where the bra band sits properly. This measurement plays a crucial role in determining the bra’s band size - for example, 32,34,36, etc.
How to Measure Underband (Underbust) Accurately
Replace 5 body senses and the content below with “How to Measure Underband (Underbust) Accurately”
- Use a soft measuring tape.
- Stand straight and breathe normally.
- Place the tape right under your bust, snugly around your ribcage.
- Note the measurement in inches.
Tip from Shyaway: The tape should feel snug but not tight—you should be able to slip one finger underneath for comfort.
Why It Matters
Your underbust measurement determines your bra’s foundational support. A loose band means your bust isn’t getting enough lift, putting pressure on your shoulders. On the other hand, a too-tight band restricts breathing and irritates your skin.
What Is Overbust?
Your overbust refers to the measurement taken across the fullest part of your bust, that is usually across the nipples. This measurement helps determine your cup size(A, B, C, D, etc.)
How to Measure Overbust Accurately
- Wear a non-padded, well-fitting bra (or go braless if comfortable).
- Wrap the measuring tape around your fullest bust area, usually across the nipples.
- Stand upright, keeping your arms relaxed at your sides.
- The tape should be level and not tight.
- Record the measurement in inches.
Note: Your cup size is calculated by subtracting the underbust measurement from the overbust. The difference between the two defines your cup letter.
What Is the Difference Between Underbust and Overbust?
The difference between overbust and underbust is the formula used to determine your cup size. Here’s a quick reference:
Difference (in inches) Cup Size
| Inches | Cup Size |
| 1 | A |
| 2 | B |
| 3 | C |
| 4 | D |
| 5 | DD/E |
| 6 | F |
For example, if your overbust is 36 inches and your underbust is 32 inches, the difference is 4 inches, meaning you’re likely a 32D.
Understanding Cup Size with Overbust & Underbust Difference
Let’s take this a step further and understand how the full bra size is calculated:
Measure Underbust: Suppose you get 31 inches. Round it to the nearest even number → 32 (band size).
Measure Overbust: You measure 35 inches.
Cup Calculation: 35 (overbust) - 32 (band) = 3 inches → Cup size C.
Your correct bra size = 32C.
If you are still confused about finding the right size of your bra, then this bra size calculator helps you find the correct fit.
Common Mistakes to Avoid While Measuring
Despite the accurate measurements, many women still face ill-fitting bras. Here’s why:
1. Measuring over Clothes
Wearing clothes while measuring gives you inaccurate measurements. Always measure directly over the skin or a fitted non-padded bra. This gives you the exact measurement that will help you find your size.
2. Wearing a Padded or Push-up Bra
A padded or push-up bra gives extra volume to your bust and avoids your natural shape for measuring. So it is better to avoid them.
3.The Tape Is Too Loose or Too Tight
The measuring tape should sit snugly but comfortably. If it is too tight, you’ll end up choosing a smaller size. If it is too loose, the result is a larger size than you need.
4. Not Updating Your Size Regularly
Our bodies change due to age, hormones, weight fluctuations, and even posture. Shyaway recommends re-measuring every 6–12 months to ensure you’re wearing the right size.
Final Thoughts
Understanding what is underbust and what is overbust may seem small, but it has a big impact on your daily life. A perfect bra size improves comfort, confidence, and posture. Measuring accurately and understanding these terms can help you avoid years of discomfort from ill-fitting bras.
FAQ’S
- Can my bra size change over time?
Yes! Pregnancy, weight loss/gain, hormonal changes, and aging can all impact your bra size.
- How often should I measure my underbust and overbust?
Every 6–12 months is ideal, or after any significant body change.
- What if my overbust and underbust don’t match a chart?
Shyaway offers free consultation and tools like our Bra Fit Calculator to help you find your unique fit.