The Fitting Room: Find Your Size

Finding the right size is the starting point for getting the right fit. But sizing lingerie is not simply a matter of taking a measurement and matching it to a number.

Bras are particularly complicated. Traditional bra sizing starts with two measurements, but two measurements alone do not tell the whole story. Cup names change across manufacturers and countries. Changing a band size changes the volume represented by a cup letter. And even when the size is right, a bra's style and construction may not be right for your breasts or body.

Other lingerie categories have their own sizing rules. Panties and shapewear require you to consider all the body measurements covered by the garment. Hosiery commonly uses height and weight. Slip sizing includes an industry length convention that is easy to misunderstand.

The goal of this section is to give you the sizing tools, charts, explanations, and fitting knowledge you need to make a better-informed choice before you buy.

Bra Sizing

Find Your Bra Size

Your Bra Size Is a Starting Point

Traditional bra sizing starts with two measurements:

• Your underbust measurement, which helps determine your band size.
• Your full-bust measurement, taken around the fullest point - or apex - of your breasts, which helps estimate your cup size.

Those two numbers are useful. But they cannot account for everything that affects bra sizing and fit.

HerRoom therefore gives you two ways to start:

Bra Size Calculator >

Use your measurements to calculate a starting bra size.

Find Your Best Bra Size Quiz >

For a more thoughtful answer, the quiz goes beyond two measurements and asks detailed questions about how your current bras actually fit.

From there, this section will help you understand how to measure properly, Universal Cup Sizing™, sister sizes, international sizing, larger cup sizes, how bra style affects fit, and how to test whether a bra really fits.

There is no one perfect bra size. The goal is to find your best starting size and then confirm the fit on your own body.

Bra Size Calculator

Start With Two Measurements

HerRoom's Bra Size Calculator uses your underbust and full-bust measurements to calculate a starting bra size.

You will need a soft sewing tape measure that can conform to the curves of your body. A rigid ruler, construction tape measure, string, or another measuring tool is not a good substitute.

For the most useful result, wear your newest, best-fitting everyday bra in a traditional bra size - for example 34C, 36DD, or 34D4 - rather than a bralette or another S/M/L-sized style. An underwire bra is preferred if you normally wear underwires because it helps position and support the breasts while you measure. The bra should be unpadded and should not be a minimizer or sports bra.

If your breasts appear to sag in the bra, adjust the straps first. Ideally, the fullest point of your breasts - the apex - should be approximately halfway between your shoulder and elbow before taking your full-bust measurement.

Measurement 1: Underbust

Wrap the sewing tape around your ribcage directly beneath your breasts. Look in a mirror and make sure the tape is parallel to the floor all the way around your body. If the tape angles upward or downward, you can get the wrong measurement. The tape should be snug without binding. Exhale completely before reading the measurement, then round to the nearest whole inch.

Measurement 2: Full Bust

Stand straight with your arms relaxed at your sides. Wrap the sewing tape around the fullest point of your breasts, keeping it parallel to the floor. The tape should just touch your body; it should not hang loosely or compress your breast tissue. Your breasts need to be properly supported when this measurement is taken. That is one reason the bra you wear while measuring can change the result.

Need the full measuring method? See How to Measure Your Bra Size, including exact tape placement, why the bra you wear matters, and special considerations for larger and more pendulous breasts.

Why the Calculator Is Only a Starting Point

HerRoom has tested tape-measure sizing on real women and found that results can change depending on where the tape is positioned and which bra the woman is wearing. Breast firmness, breast position, back width, shoulder proportions, and larger cup sizes can also make measuring less predictive. Tape-measure cup calculations become less reliable above a D cup.

The Bra Size Calculator gives you a useful starting point. It does not get the final vote.

Two Measurements Don't Tell the Whole Story

If you want a more thoughtful answer about whether your current size - or another size - may be better, take HerRoom's Find Your Best Bra Size Quiz. It considers information that two measurements cannot capture by asking detailed questions about what is actually happening when you wear your current bras.

Take the Find Your Best Bra Size Quiz

Find Your Best Bra Size Quiz

A More Thoughtful Way to Find Your Best Bra Size

HerRoom's Find Your Best Bra Size Quiz was five years in development. Instead of relying solely on a tape measure, the quiz asks detailed, targeted questions about how your current bras fit - including many questions that are not commonly asked in bra-sizing quizzes.

Your answers help fine-tune the result based on what is actually happening when you wear a bra. Bra sizing is subjective. The quiz therefore does not pretend that someone else can declare one mathematically "perfect" bra size for you.

You are ultimately the woman who is going to wear it.

Your results give you a recommended bra size as a better-informed starting point and include a summary of your answers for future reference.

Larger Than a D Cup?

Your results also include your Universal Cup Size (UCS®). This becomes particularly important above D because manufacturers do not all use the same cup letters for the same cup volume.

Take the Find Your Best Bra Size Quiz

How to Measure Your Bra Size

The Details Matter

Measuring for a bra looks simple, but small differences in how you measure can change your result. Use a soft sewing tape measure and, when possible, have someone help you.

Wear your newest, best-fitting unpadded everyday bra. If you normally wear an underwire bra, an underwire is preferred. Whenever possible, use a traditionally bra-sized style rather than an S/M/L bralette. Do not measure in a minimizer, sports bra, or heavily padded bra because those styles can reposition or compress your breasts.

Before measuring, adjust your straps so your breasts are supported and your breast apex sits at approximately the midpoint between your shoulder and elbow.

Step 1 - Measure Your Underbust

Position the tape directly beneath your breasts. Keep it level and parallel to the floor. The tape should be snug without binding. Exhale completely before taking the measurement. Round fractions to the nearest whole inch. Placement matters: a tape positioned too high or too low can produce a misleading result.

Step 2 - Measure Your Full Bust

Stand straight with your arms at your sides. Measure around the fullest point of your breasts, keeping the sewing tape parallel to the floor. The tape should lightly touch your breasts without compressing them.

Your breasts should be supported while measuring. If you are D cup or larger and your best-fitting bra is so tight that it distorts the bust measurement, HerRoom guidance allows for measuring without a bra while manually supporting the breasts in their proper position and having another person take the measurement.

Universal Cup Sizing™

The Same Cup Volume Can Have Different Names

Above a D cup, bra sizing gains another layer of confusion. A manufacturer may call a particular cup volume DDD, another may call it F, and another may call it E. The woman's breasts did not change. The cup volume did not change. Only the name changed.

HerRoom created Universal Cup Sizing™ (UCS®) to give cup volumes above D one consistent reference: D1, D2, D3, D4, D5, D6...

Why UCS Gives You More Choices

For example, UCS D3 is called DDD/F in US sizing, E in UK sizing, and F in European sizing. But UCS does more than translate the letters.

If your bra size is 34D3, you can search HerRoom using 34D3 and see bras available in your band and cup volume regardless of what an individual manufacturer calls that cup size. You do not have to know in advance whether a brand calls your cup DDD, F, E, or another equivalent designation.

Your UCS lets you shop by cup volume rather than by one manufacturer's cup letter.

Find Your Universal Cup Size

Sister Bra Sizes

Changing the Band Changes the Cup

One of the most common mistakes women make with bra sizing is assuming that the cup letter means the same thing on every band size. It does not. Cup volume changes when band size changes.

Suppose you wear a 36C. If your band fits and you only need a larger cup, try 36D. If your band fits and you need a smaller cup, try 36B. But if you want to change the band without substantially changing the cup volume, you must also change the cup letter.

• 36C -> 34D for a smaller band with approximately the same cup volume.
• 36C -> 38B for a larger band with approximately the same cup volume.

The Common Mistake

A woman in a 36D who decides her band is too loose may simply buy a 34D. But she has changed two things: she reduced the band size and reduced the cup volume. If the 36D cup volume was correct and only the band needed to become smaller, her sister size is 34DD.

Likewise, moving from a 36D to a 38D increases both the band and the cup volume. To maintain approximately the same cup volume while increasing the band, she would move toward 38C.

This is why a cup letter should never be considered without its band number.

International Bra Sizing & Size Conversion

Bra Sizes Don't Speak One Language

Bra sizing systems vary by country. The United States, United Kingdom, continental Europe, France, Italy, Australia, and Japan use different combinations of band numbers and cup letters. That means the size printed on one bra may look very different from the equivalent size manufactured under another country's system.

Large Cup & Extended-Size Sizing

Above D, the Letter Can Be Misleading

The farther you move above D, the more important it becomes to understand which sizing system a manufacturer is using.

Consider the letter G. In US and European sizing, G represents UCS D4. In UK sizing, G represents UCS D6 - two cup volumes larger. So two bras labeled "G" can be very different cup sizes.

The cup letter alone is not enough. Confirm the UCS.

Don't Assume a Bra Isn't Made in Your Size

A UK FF is UCS D5. That same D5 cup volume is called H in US and European sizing. If you know yourself only as a US H and do not know that UK FF represents your cup volume, you can easily overlook many bras that actually come in your size.

That is one of the reasons UCS can reveal substantially more choices to women in larger cup sizes.

Before you rule out a bra above D, check the UCS.

Make Sure You're Actually Inside the Bra

Larger-cup women also need to be especially careful about how they put on a bra before deciding whether the cup fits. Breast tissue can remain under the arm, beneath an underwire, or outside the cup and make a cup appear adequate when it is actually too small.

Lean forward and make sure all breast tissue is brought up and into the cups and sits above and inside the underwire.

Universal Cup Sizing™

International Bra Sizing and Size Conversion

Bra Size vs. Bra Fit

You Can Have the Right Size and the Wrong Bra

Knowing your bra size tells you your band and breast volume. It does not tell you whether every bra made in that size will work with your breasts, body proportions, and wardrobe.

Two women can wear exactly the same bra size and need very different bra constructions because their breast separation, upper fullness, position, projection, shoulder width, torso height, tummy shape, and other characteristics are different.

Right Size, Wrong Style: Petite or Short-Waisted

A petite or short-waisted woman can have the right bra size and still find that a full-coverage bra overwhelms her frame. The cups or underwires may rise too high under her arms. The bra may cover more of her chest than feels proportionate. Her straps may not adjust short enough. If strap length is the problem, HerRoom's Fully Adjustable Straps filter can narrow the choices to bras whose straps adjust along their full length.

That does not necessarily mean her bra size is wrong. A demi, balconette, or plunge bra may work better because these styles often use shorter underwires and more compact frames.

Right Size, Wrong Style: High Tummy

A woman with a higher or fuller upper tummy may also be in the correct bra size but find that a tall underband rolls or flips upward when she sits. An arched center panel creates space for the top of the tummy to rise beneath the bra. Bandless bras or bras with less fabric below the cups can also work better.

Right Size, Wrong Cup Shape

A bra can also have the correct cup volume but still gap, wrinkle, poke, or feel wrong because the cup shape, depth, underwire geometry, strap position, or breast-apex location does not match the woman.

Sometimes changing the size is the answer. Sometimes changing the bra style is the answer.

Before automatically moving up or down a size, ask whether the bra's construction is compatible with your breasts and body.

For more detail on how bra styles are constructed and which styles solve different fit and wardrobe needs, see Section 3 - Learn About Bras.

For more detail on how breast characteristics and body proportions affect fit, see Section 5.1 - Know Your Breasts.

Perfect Fit Checklist & Fit Tests

Don't Just Look at the Bra. Test It.

A bra may look fine while you are standing still and still fail when you move, sit, raise your arms, or remove the support of the straps. HerRoom's fitting method therefore includes practical fit tests in addition to visual checks.

1. Band Test

The band should sit level and parallel to the floor around your body. With a new bra fastened on its loosest set of hooks, slide a hand under the center of the back band and rotate the hand perpendicular to your back. The hand should feel firmly wedged; the band should not pull substantially farther away. A band that rides up or allows breast tissue to fall underneath is generally too large.

2. Cup Test

Your cups should contain the breast tissue without obvious wrinkling, gaping, or overflow. Overflow at the neckline or armhole can signal a cup that is too small; substantial empty space can signal too much cup volume - or the wrong cup shape or style.

3. Raise-Your-Arms Test

Raise both arms above your head. The bra should stay where it was. If the bra rides up your torso or breast tissue falls out beneath the cups, the band may be too large.

4. Breasts-in-the-Middle Test

Once your breasts are correctly positioned and supported, their apex should generally sit approximately halfway between your shoulder and elbow. If the bust sits substantially lower, your band may not be providing enough support, or in larger cup sizes you may need a bra construction with more supportive seaming.

5. Stoop, Scoop & Smooth

Lean forward so your breasts fall fully into the cups. Using the opposite hand, bring breast tissue forward from the sides and upward from beneath the breasts so all breast tissue is positioned inside and above the underwire. Then smooth the tissue along the neckline. If overflow remains after you are properly positioned, you may need more cup volume - or, depending on the bra, a different style.

6. Underwire Test

The underwire should completely surround your breast base and rest in your natural breast crease. It should not sit on breast tissue. If the outer wire catches breast tissue or your arm, the cup may be too small or the wire too narrow. If the wire reaches too far into the armpit, you may need less cup volume or a bra with shorter underwires. Petite and short-waisted women often do better with shorter underwires found in demi, balconette, and plunge constructions.

7. Center Panel Test

For most underwire bras, the center panel should rest comfortably against the sternum. Important exceptions include touching or splayed breasts, chest-wall shape, wireless construction, and some minimizer engineering.

8. Bra Strap Test

The straps should lie flat without painfully digging into your shoulders or continually slipping off. Now remove the straps from your shoulders. The bra should remain substantially in place. If it drops significantly, the straps may be doing too much of the work and the band may be too loose.

9. Hook Test

A new bra should fit snugly on its loosest hook setting. This gives you room to move inward to tighter settings as the elastic relaxes with wear.

10. Sitting & Leaning Test

Sit down in the bra. Is it still comfortable? Your ribcage changes when you sit, and the upper tummy can rise toward the bra. If the lower band becomes uncomfortable or flips upward, an arched center panel or a bra without a substantial underband may work better. While sitting, lean forward. If the cups suddenly gap, the bra may provide more coverage than your physique needs. A lower-coverage style may be a better match.

11. Jump Up & Down Test

This is especially useful for larger cup sizes and sports bras. Hop or perform several jumping jacks. Your breasts should remain contained. Significant upward/downward movement, painful bounce, or breasts escaping the cups can indicate an inadequate band, cup, or support level. Judge the bra according to its intended purpose; a lower-coverage everyday bra is not engineered like a high-impact sports bra.

For more detail on breast separation, torso height, tummy shape, shoulders, sternum, and other characteristics that can affect these fit tests, see Section 5.1 - Know Your Breasts.

Complete HerRoom Bra Fit Tips and Tests

Solve a Specific Bra Fit Problem

Understanding Brand & Product-Specific Size Charts

Your Starting Size Is Only Part of the Shopping Decision

Manufacturers use different sizing systems and grading conventions. HerRoom therefore gives you sizing information for the actual product you are shopping.

On desktop, opening the Size dropdown automatically displays the product's size chart for comparison.

On mobile, the size chart does not automatically open with the size selector. Select the Size Chart link next to the size selector to open the applicable chart.

For bras, the PDP also identifies whether the manufacturer's sizing is US, UK, or EU directly beneath the Size Chart link.

Every Bra Chart Helps Translate the Manufacturer's Size

HerRoom's bra product size charts do more than list the sizes available. They show the manufacturer's cup size alongside UCS®, US equivalent, EU equivalent, and UK equivalent. This lets you confirm the actual cup volume before selecting the manufacturer's size.

Find the manufacturer's bra size in the first column, then read across the row to see its UCS cup volume and equivalent US, EU, and UK cup sizes.

Product-Specific Sizing Applies Beyond Bras

The same principle applies to panties, shapewear, hosiery, slips, sleepwear, and other products. Check the Size Chart for the item you are considering rather than assuming one brand-wide chart fits every product.

Fit Lab Findings Add Another Layer

HerRoom does not rely only on the manufacturer's chart. Products also go through the HerRoom Fit Lab, where representative samples are fitted, measured, photographed, and analyzed. Those product measurements appear in Fit Lab Findings - formerly called Fitter's Comments - to give you additional information about the actual product.

HerRoom measures a representative size rather than every size in a garment's range. The measured size is identified so you know exactly what the published measurements represent.

• Most panties: size Small.
• Full-figure panties: size Large.
• Bras: a representative size appropriate to the bra's size range, such as 34C, 32DD, or a larger UCS size such as 34D6.

The purpose is to provide a consistent reference point for comparing the product's actual proportions and construction - not to imply that every size in the range has identical measurements.

Use the Layers Together

• Your starting size tells you where to begin.
• UCS and international charts help you understand the sizing language.
• The product-specific size chart tells you how that product is sized.
• Fit Lab Findings, Tomima's Tips™, and other HerRoom product information tell you what HerRoom learned from evaluating the actual item.
• Your body tells you whether the product fits.

B. Panty Sizing

Find Your Panty Size

Panty sizing generally uses your waist and hip measurements. But reading the chart correctly is just as important as taking the measurements.

The Rule: Your Size Must Accommodate Every Required Measurement

The correct size is the one in which all of your required measurements fit within the manufacturer's ranges. Do not average your waist and hip measurements. Do not select a size between the two. And do not choose a smaller size simply because it is closer to the size you usually wear.

Example 1

Suppose a 28-inch waist falls in M/6 while 40-inch hips require L/7. Your correct choice is L/7 because the hips require the larger size.

Example 2

Suppose your measurements are 38-inch hips and a 40-inch waist. The hips fit a much smaller size, but the 40-inch waist requires 5X/12 in a full brief that reaches the natural waist. Choose 5X/12. The brief will be loose or baggy through the hips because that size was designed for larger hips as well.

That May Mean You Need a Different Panty Style

The sizing is not wrong. The proportions of that particular panty style are not ideal for this woman's proportions. A bikini may give her a better fit because it sits lower on the body and does not extend up to the natural waist. Her 40-inch natural-waist measurement therefore does not control the fit in the same way it does in a full brief.

Use every measurement required for the parts of the body the garment actually covers. If the size needed to accommodate those measurements gives you a poor fit because of your proportions, consider changing the panty style rather than choosing the wrong size.

C. Shapewear Sizing

Find Your Shapewear Size

Shapewear sizing follows an important rule: choose the size that accommodates every measurement required by the manufacturer's chart.

If your waist fits one size and your hips fit another, choose the size that accommodates both. Do not average the measurements. Do not size down because you think smaller shapewear will provide more control. The level of shaping should come from the garment's construction and control level, not from wearing the wrong size.

When Your Measurements Land in Different Sizes

If the waist requires XL and the hips require L, choose XL. If the hips require 2X and the waist requires L, choose 2X. The larger size is not automatically "too big." It is the size the manufacturer has designed to contain all of the required measurements.

If that size becomes noticeably loose in another area, the issue may be the proportions or style of that particular garment. Another shapewear style may match your figure better.

When a One-Piece Body Shaper Doesn't Match Your Proportions

A one-piece body shaper has to fit several parts of your body at the same time. If your bust, waist, hips, or torso measurements do not fall into the same size on the manufacturer's chart, choosing the size that accommodates your largest required measurement may leave another area too loose.

Do not solve that problem by sizing down. Consider dividing the job between two shapewear pieces instead.

• Choose a shaping camisole in the size that correctly fits your upper body.
• Choose a shapewear biker short or shaping panty in the size that correctly fits your waist, hips, and lower body.

Together, two correctly sized garments can often provide much the same shaping coverage as a one-piece body shaper while allowing each area of your body to be fitted correctly.

Sometimes the best shapewear fit comes from two correctly sized pieces rather than one incorrectly sized garment.

Why There Is No Single HerRoom Shapewear Size Chart

Shapewear comes in many constructions - briefs, thigh shapers, waist cinchers, camisoles, bodysuits, torsettes, full-body shapers, and other styles. They cover different parts of the body and manufacturers size them differently. For that reason, the most useful sizing reference is the product-specific chart on the PDP.

For more detail on shapewear styles, control levels, and fit, see Section 8.2 - Shapewear Fit & Style Guide.

D. Hosiery & Tights Sizing

Find Your Hosiery Size

Hosiery is commonly sized using height and weight together. Locate your height on the chart and then confirm that your weight falls within the same size range. Both measurements matter. Do not choose a smaller size simply because one of the two measurements fits it.

Product-Specific Charts Still Control

Hosiery sizing varies by manufacturer, so use this general chart to understand the system, but always check the product-specific Size Chart before making your final selection.

E. Slip Sizing

Find Your Slip Size

Slip sizing includes one industry convention that can be confusing if you do not know what the stated length means.

Full Slip Length Is Measured From the Waist Down

If a product is described as a 32-inch Full Slip, the 32 inches does not mean the garment measures 32 inches from the top of the shoulder strap to the hem. Traditionally, the lingerie industry states a full slip's length from the waist down. In effect, the published number gives you the same type of waist-to-hem length used for a half slip.

A 32-inch full slip is not a 32-inch-long garment from top to bottom.

HerRoom Gives You More Information

HerRoom's Fit Lab Findings provide actual product measurements on full slips, so customers can see more than the traditional industry length designation. As with HerRoom's other product measurements, the measurements are taken on a clearly identified representative size rather than every size in the product range. That gives you a consistent reference for understanding the actual garment while keeping the manufacturer's traditional slip-length designation intact.

Using Size Charts Successfully

Size charts are valuable because they narrow your choices before you order. But they need to be used correctly.

• For bras, start with your best bra size, understand the sizing system, use UCS when you are above D, check the product-specific chart, and then confirm the fit.
• For panties and shapewear, every required measurement needs to fall within the size you select. Do not average measurements to create a size the manufacturer did not design.
• For hosiery, use both height and weight.
• For slips, understand exactly what the stated garment length represents.

And whenever you are shopping on HerRoom, check the product's Size Chart, Fit Lab Findings, Tomima's Tips™, and other product-specific fit information before making your final decision.

A size gets you into the right place to start. Understanding how that size relates to your body, the garment, and the manufacturer's sizing system is what helps you make a better choice.