Bra Fit Measurement Guide
Last updated: April 21, 2025
This guide helps you determine your bra size using basic tools at home. You can measure in inches or centimeters based on your preference.
Follow the instructions below using a soft measuring tape for best results.
How to Prepare
Before you begin, make sure you have the following items ready:
You'll need a soft measuring tape, a mirror to check tape alignment, and a notepad to record your measurements. Wearing a lightly lined bra or snug top can improve accuracy.
Tips for Accurate Measuring
- Clothing: Choose something fitted, non-padded, and lightweight.
- When: Measure when you're most comfortable, ideally a few days post-cycle to avoid natural size fluctuations.
- Where: Use a well-lit, private space with a mirror to guide tape placement.
- Tools: Keep a notepad or phone nearby to note your measurements.
Step 1: Measure Your Band
Wrap the measuring tape around your torso, just under your bust. Ensure it is level and snug, but not tight.
Tip: If you're between numbers, round to the nearest whole number.
Step 2: Measure Your Bust
Measure around the fullest part of your chest. Make sure the tape is even and not pressing into the body.
Tip: If in between values, round up or down based on comfort.
Step 3: Calculate Your Size
Subtract your band measurement from your bust measurement. The difference tells you the cup size.
Example: Band = 34", Bust = 36" → Difference = 2" → Cup Size = B → Final Size = 34B
- 1 inch = A cup
- 2 inches = B cup
- 3 inches = C cup
- And so on…
Check the international size chart below for reference across sizing systems.
Cup Size Chart (Global Reference)
| Difference in (cm) | UK | US | EU | FR | AU |
|---|
| <1 | AA | AA | AA | AA | AA |
| 1 (2.5) | A | A | A | A | A |
| 2 (5.1) | B | B | B | B | B |
| 3 (7.6) | C | C | C | C | C |
| 4 (10.2) | D | D | D | D | D |
| 5 (12.7) | DD | DD/E | E | E | DD |
| 6 (15.2) | E | DDD/F | F | F | E |
| 7 (17.8) | F | DDDD/G | G | G | F |
| 8 (20.3) | FF | H | H | H | G |
| 9 (22.9) | G | I | I | I | H |
| 10 (25.4) | GG | J | J | J | I |
| 11 (27.9) | H | K | K | K | J |
| 12 (30.5) | HH | L | L | L | K |
| 13 (33.0) | J | M | M | M | L |
| 14 (35.6) | JJ | N | N | N | M |
| 15 (38.1) | K | O | O | O | N |
| 16 (40.6) | KK | P | P | P | O |
| 17 (43.2) | L | Q | Q | Q | P |
| 18 (45.7) | M | R | R | R | LL |
For full regional sizing, visit brasizecalculator.com/chart
Step 4: Use the Online Calculator
Enter your measurements in inches or centimeters. The tool will suggest:
- Your recommended bra size
- Two alternative sizes for flexible fit
- Top brand suggestions
- Style suggestions tailored to your shape
Manual Calculation Option
Use the band + bust difference and size chart to find your fit manually.
Printable chart available at brasizecalculator.com/chart
Note on Traditional Sizing
Some brands add inches to underbust measurements to get band size. For example, 34" underbust may become 38" band.
Check the size method your preferred brand uses.
Step 5: Try On and Adjust
Once you have your size, try different brands and styles for the best comfort and support.
Fit can vary, so always prioritize feel and support.
Frequently Asked Questions
To find your correct bra size, you need two measurements:
- Band Size: Measure around your ribcage, just under your bust. Make sure the tape is snug but not too tight.
- Bust Size: Measure around the fullest part of your bust, making sure the tape is parallel to the floor and not too loose.
Once you input these measurements into the calculator, it will generate your bra size.
Yes! Our calculator allows you to switch between inches and centimeters. You can input your measurements in either unit, and the calculator will automatically convert them.
Our calculator is designed to be as accurate as possible by using standard sizing charts from various popular brands. However, your comfort and preference may vary depending on the style and fit of each brand. Use the results as a starting point and try different sizes if needed.
Bra sizes may vary between brands due to differences in their sizing systems. Our calculator provides brand-specific recommendations, helping you find the closest match for each brand.
Our bra size calculator supports a wide range of sizes, including smaller and plus sizes. We include band sizes from 27 in to 56 in (60 cm to 120 cm) and cup sizes from A to Z, covering most standard bra brands.
To ensure accurate results, the bust size dropdown adjusts based on your selected band size. This is because bust size is relative to band size, and this dynamic dropdown helps you pick the most appropriate range for your bust.
Our calculator includes sizing charts for popular brands such as Marks & Spencers, Victoria's Secret, Calvin Klein, and Chantelle. We continually update our list of brands to include more options, so you can expect a variety of choices.
Yes! The calculator provides sizing conversions for different regions, including US, UK, EU, FR, AU, and JP. Just input your measurements, and the calculator will convert your size based on the selected region.
Our calculator works for most bra types, including t-shirt bras, sports bras, balconette bras, and more. However, specialized bras like maternity or post-surgical bras may require additional considerations.
Currently, the calculator does not store personal data for privacy reasons. However, you can take a screenshot of your results or write them down for future reference.
While many use tools like ‘a bra that fits calculator,’ our advanced bra size calculator goes a step further by incorporating brand-specific size charts. These charts are sourced directly from all major bra brands, ensuring a more accurate fit tailored to the specific sizing standards of each brand.
Brand-specific charts account for variations in sizing systems used by different brands. For example, a 34C in one brand might fit differently than the same size in another. By using brand-specific data, our calculator provides precise recommendations for each brand, helping you find a bra that truly fits.
Yes! Our calculator is designed to work with all major brands. Whether you prefer Victoria’s Secret, ThirdLove, or any other brand, our tool uses their official sizing charts to give you the most accurate size.
Absolutely. Our calculator includes charts from US, UK, EU, and other international sizing systems. You can easily convert your size to match the specific standards of your preferred brand or region.
Traditional methods often rely on generic calculations, which may not account for differences between brands. Our calculator combines band and cup measurements with brand-specific data to give you an exact size recommendation tailored to your preferred brand's fit.
No, you don’t need to know your current size. Simply measure your band and bust size as instructed, and our tool will calculate the most accurate size for your preferred brand, even if you’re unsure about your current fit.
Our bra size calculator provides results that are highly comparable to in-store fittings. With brand-specific charts and precise measurements, it minimizes errors and saves you the time and effort of visiting a store.
Yes, our calculator makes it easy to switch between brands. Once you input your measurements, you can see size recommendations for different brands instantly, ensuring you get the right fit no matter your preference.
