Calculate Bra Size

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Bra Fit Measurement Guide

Last updated: April 21, 2025

Prefer visuals? Our infographic walks you through each step.

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)UKUSEUFRAU
<1AAAAAAAAAA
1 (2.5)AAAAA
2 (5.1)BBBBB
3 (7.6)CCCCC
4 (10.2)DDDDD
5 (12.7)DDDD/EEEDD
6 (15.2)EDDD/FFFE
7 (17.8)FDDDD/GGGF
8 (20.3)FFHHHG
9 (22.9)GIIIH
10 (25.4)GGJJJI
11 (27.9)HKKKJ
12 (30.5)HHLLLK
13 (33.0)JMMML
14 (35.6)JJNNNM
15 (38.1)KOOON
16 (40.6)KKPPPO
17 (43.2)LQQQP
18 (45.7)MRRRLL

For full regional sizing, visit brasizecalculator.com/chart

Use our online calculator for quick results.

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.

Frequently Asked Questions

To measure your bra size at home, use a soft measuring tape. First, measure your band size by wrapping the tape around your ribcage, just under your bust, keeping it snug.

For the cup size, measure around the fullest part of your bust. Subtract the band size from the bust size; each inch difference represents a cup size (e.g., 1 inch = A, 2 inches = B, and so on).

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.

After measuring your bust and band size, subtract the band size from your bust measurement. The difference determines your cup size:

1 inch = A cup, 2 inches = B cup, 3 inches = C cup, and so on.

For example, if your bust is 36 inches and your band is 34 inches, the difference is 2 inches, meaning a B cup.

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.

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 or 60 cm to 120 cm and cup sizes from A to Z, covering most standard bra sizing systems.

If your size is in between, we recommend trying both sizes and choosing the one that feels more comfortable.

You can also look for bras labeled as "sister sizes" for a more tailored fit.

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.

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.

Currently, bra size 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.

The biggest bra size varies by manufacturer, but some brands offer cup sizes up to an O or P. Band sizes can go up to 58 or larger. Specialized lingerie stores and custom bra makers may accommodate larger sizes.

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.

Bra sizing can vary slightly between brands due to different sizing systems and fit models. While most brands use similar band and cup measurements, some may run smaller or larger. It's recommended to try on bras from different brands or refer to size charts specific to each brand.

A good-fitting bra should:
  • Be snug around the band without digging into your skin.
  • Have cups that fully contain your breasts without gaps or spillage.
  • Have straps that sit comfortably on your shoulders without slipping off or digging in.
If you notice discomfort, you may need to try a different size.

Signs include the band riding up your back, straps digging into your shoulders, gaping or spillage from the cups, and discomfort or pain during wear. These indicate that you might need a different size.

Wearing the wrong bra size can lead to discomfort, back and shoulder pain, skin irritation, and poor posture. Ill-fitting bras, especially too tight or too loose, can also affect breast shape and support.

It’s normal for your bra size to change due to factors such as weight changes, pregnancy, or aging. We recommend measuring your bra size every six months to ensure a proper fit.

To support sagging breasts, look for bras with firm underwire, full coverage cups, and wide straps. Minimizer bras, full-cup bras, and bras with side panels can provide lift and structure, giving a firmer appearance.

A minimizer bra is designed to reduce the appearance of the bust by distributing breast tissue more evenly. It’s ideal for women with larger breasts who want a smoother look under clothing or wish to reduce projection.

A push-up bra enhances cleavage by lifting the breasts with padding, typically pushing them together. A balconette bra, on the other hand, offers a more natural lift and wide-set shape, revealing the upper part of the bust and providing a rounded look without significant padding.

A water bra contains liquid or gel inserts in the cups to enhance cleavage and provide a fuller appearance. It’s often used by those looking for extra volume or a more rounded shape.

A T-shirt bra is seamless and designed to be invisible under tight clothing. It provides smooth, full coverage. A plunge bra, however, has a deep V-shaped neckline, making it ideal for low-cut tops while enhancing cleavage.

You should replace your bra every 6-12 months, depending on wear and care. Signs it’s time for a replacement include stretched-out bands, misshapen cups, or loss of support. Wearing a rotation of bras helps them last longer.

Hand washing in cool water with mild detergent is best to maintain a bra’s shape. If using a washing machine, place bras in a mesh bag and use a gentle cycle. Always air dry bras to prevent elastic damage.

You can get professionally fitted for a bra at lingerie stores, department stores with lingerie sections, or specialty bra shops. Some well-known stores, like Marks & SPencers, Victoria’s Secret, etc. offer free bra fitting services.

A sports bra is designed for high-impact activities and offers more compression and support to minimize breast movement. It usually has wider straps, a racerback design, and moisture-wicking fabric. A regular bra focuses more on shaping and comfort for everyday wear.

No, there is no scientific evidence that links not wearing a bra to sagging breasts. Sagging is influenced by factors such as genetics, age, and weight fluctuations rather than bra-wearing habits.

Bra sizing systems differ by country due to variations in measurement standards and conventions. For example, US, UK, and European sizes use different scales, which can result in different labels for the same bra measurements.