Bra Size Calculator
The bust size is the loose circumference measured around the chest over the fullest part of the breasts.
The band or frame size is the firm circumference, fitted not tightly, measured directly underneath the breasts.
Bra Size Converter
Convert bra sizes between different international sizing standards.
Find Your Perfect Fit with Our Accurate Bra Size Calculator
An accurate bra size calculator is an online tool designed to determine your correct band and cup size using simple body measurements. Choosing the right size improves comfort, posture, and breast support while preventing shoulder pain and long-term health issues. Our calculator provides precise results by analyzing bust and underbust measurements, ensuring a reliable fit every time. With accuracy comparable to professional fittings, this calculator helps women shop confidently for bras from leading brands in styles that truly match their shape.
Why Correct Bra Sizing Matters
Wearing a bra that doesn’t fit correctly can lead to a host of problems. Many women experience common issues like shoulder and back pain, constant strap readjustments, and red marks from digging wires or bands. Beyond these everyday annoyances, a poorly-fitted bra can have more serious, long-term consequences.
Research and expert opinions confirm that improper support can contribute to poor posture, skin irritation, and even affect breast tissue health over time. A correctly-sized bra provides the right support, distributing weight evenly and allowing you to move freely and confidently. This is why knowing your true size is so important.
Common Signs You’re Wearing the Wrong Bra Size
Many of us are wearing the wrong size without even realizing it. Here are the clear signs that your bra isn’t providing the support you need:
The bra band rides up your back instead of staying level.
Your breasts are spilling out of the top or sides of the cups.
The center panel of the bra doesn’t lie flat against your sternum.
The straps are digging into your shoulders or constantly slipping down.
You notice gaps in the cups, suggesting they are too large.
If any of these sound familiar, it’s a strong signal that it’s time to re-evaluate your size.
How to Measure for a Bra: A Modern Approach
Historically, many bra calculators used a flawed “add 4/5 inches” rule. This outdated method often leads to an inaccurate fit. Our approach, aligned with modern fitting standards, relies on a simple, two-step method to get you the most accurate results.
Step 1: Measure Your Band Size
Wrap a flexible tape measure snugly around your rib cage, directly beneath your breasts. Keep the tape level and parallel to the floor. The number you get is your band size. This measurement should be firm but comfortable.
Step 2: Measure Your Bust Size
Next, wrap the tape measure around the fullest part of your bust. This is your bust size. Make sure the tape is relaxed and not too tight, and keep it parallel to the floor.
Calculating Your Cup Size
The difference between your bust measurement and your band measurement determines your cup size. For example:
1-inch difference = A cup
2-inch difference = B cup
3-inch difference = C cup
This method ensures a more precise fit by focusing on your unique measurements rather than a broad, generic rule.
Why Bra Sizing Varies (and What to Do About It)
One of the biggest frustrations for bra shoppers is the lack of universal sizing. A size 34B can fit differently from one brand to another, and this inconsistency is a common reason for confusion and ill-fitting bras.
Our bra size calculator addresses this by factoring in sizing variations from popular retailers and industry standards. This ensures you get a recommendation that’s not just a number, but a usable size for your next purchase, whether you’re shopping online or in-store.
Our tool takes into account measurements in both inches and centimeters, making it versatile for users across the UK and beyond.
We’ve integrated data from major UK retailers like Marks & Spencer, giving you a reliable bra size calculator M&S reference.
How to Calculate Bra Size Manually
Although our tool simplifies the process, it’s helpful to understand how to calculate bra size manually:
Measure under the bust to get the band size
Measure around the fullest part of the bust
Subtract the band from the bust measurement
Use the difference to determine cup size
If you’re ever unsure, let our calculator do the math for you.
How to Calculate Bra Cup Size
Just as important as the band is the cup. Learning how to calculate bra cup size is crucial. A common mistake is wearing a band that’s too big and a cup that’s too small. Our tool corrects this by taking both into account and cross-referencing them with industry-standard charts.
Trusted by Thousands
Thousands of women across the UK and beyond trust our bra size calculator UK to give them accurate and reliable sizing. We’ve also integrated sizing references from popular stores like Marks & Spencer, making it easy to use our bra size calculator M&S option when shopping.
FAQs
Can I use this tool during pregnancy or breastfeeding? Yes, but remember that your breast size can change significantly during this time. It’s best to measure more frequently to stay on top of your size.
How often should I measure my bra size? Your size can fluctuate due to weight changes, hormonal cycles, or age. We recommend measuring every six to twelve months to ensure your bra still fits correctly.
What if my measurement is between two sizes? For the most comfortable fit, we often recommend trying the larger of the two sizes.
Final Thoughts
Finding the right bra can be truly life-changing. It’s not just about what you wear, but how you feel. A well-fitting bra provides the comfort, support, and confidence to take on your day without distraction.
Our bra size calculator is more than just a tool; it’s a guide to understanding your body and making informed choices about your intimate apparel. Use it today and feel the difference a perfect fit can make.
Ready to find your perfect fit? Try our bra size calculator now.
