2026 Edition · 7 Sizing Systems · 100% Private

Your Complete Bra Fit & Sizing Hub

Start with your baseline size, then fine-tune fit with sister sizing, brand decoding, shape guidance, international conversions and fit-problem tools — all in one private bra-fitting hub.

Calculate My Size 📏 How to Measure First
3.8M+ women sized
7 sizing systems — US, UK, EU, FR, AU, JP, KR
0 data stored, ever
Quick Answer

Not sure where to start? Use the Bra Size Calculator to find your baseline band and cup size from measurements. Already know your size? Use the Sister Size Calculator, Brand Size Decoder, Global Size Converter or Fit Problem Solver to adjust fit, convert sizing or troubleshoot a bra that does not sit correctly.

Every Tool, In One Place

Which Calculator Do You Need?

Pick the one that matches where you are right now — each gives a real size in under a minute, no repeat measuring.

Start Here

Most people begin with these two
📐
Bra Size Calculator

The main tool — enter underbust and overbust, get your size instantly across all 7 sizing systems plus sister sizes.

Calculate now
🤖
AI Smart Fit Calculator

No tape measure handy? Answer a few fit questions instead and get a personalized size range plus style picks.

Try smart fit

By Life Stage

Bodies change — so should your calculator
🌱
Teen Bra Calculator

Built for growing bodies — gentle, judgment-free guidance toward a first accurate fit.

Open tool
🌸
Senior Bra Calculator

Accounts for the tissue and posture changes that quietly shift sizing over the years.

Open tool
💗
Plus-Size Bra Calculator

Extended band and cup ranges up to K — built specifically for full-bust fitting.

Open tool

By Purpose

Specific problems, specific tools
🔄
Sister Size Calculator

Same cup volume, different band — for when your size sells out or the band’s just not right.

Find sisters
🏃
Sports Bra Calculator

Sizing logic built around movement and impact level, not everyday wear.

Open tool
🔎
Breast Shape Identifier

Your size gets you the right fit. Your shape gets you the right style.

Identify shape
🌍
Global Size Converter

Shopping an international brand? Convert your size before you order, not after.

Convert size
🏷️
Brand Size Decoder

Why your 34DD becomes a 34G at one brand and a 34E at another — decoded.

Decode brand
🛠️
Fit Problem Solver

Spilling, gaping, digging straps — answer 5 quick questions, get a precise fix.

Diagnose fit

Shopping from a specific country?

25+ region-specific calculators — UAE, Saudi Arabia, UK, Germany, Japan, Brazil, and more, each matched to local retail sizing conventions.

Browse by Country

Start With Size, Then Fine-Tune the Fit

Finding a baseline size is only the first step. A better fit comes from combining that size with band tension, sister sizing, brand construction and the way a specific bra sits on your body.

1

Find your baseline size

Start with the dedicated Bra Size Calculator using a snug underbust and a loose full-bust measurement. That gives you a practical starting size across the sizing system you shop in.

2

Check how the band and cups sit

A calculated size still needs a quick fit check. The band should stay level, the cups should contain the breast tissue comfortably, and the center and wires should sit where the bra design intends.

3

Use sister sizes for band adjustments

If the cup volume feels right but the band does not, a sister size can change band tension while keeping a similar cup volume. Use the Sister Size Calculator instead of guessing a new size.

4

Then account for brand and shape

Cup depth, wire width, band stretch and gore height vary across brands and bra styles. Use the Brand Size Decoder, Breast Shape Identifier and Fit Problem Solver when the label looks right but the fit still feels wrong.

Something Not Sitting Right?

Full fit-problems guide
📦

Band rides up

The band is too large. Try one size down in band, one up in cup — your sister size.

💧

Cup spillage

The cup is too small. Breast tissue overflowing top or sides means it’s time to size up.

〰️

Gaping cups

The cup is too large, or the shape doesn’t match your breasts. Try one cup down.

📌

Straps dig in

The band is doing too little work. Tighten it first — straps should carry only 20% of support.

3.8M+Women sized to date
25+Country-specific calculators
7International sizing systems
0Data stored — private by design
Expert-Reviewed Guides

The Complete Bra Fitting Knowledge Hub

From first-time fitters to DD+ sizing, this hub connects measurement, fit checks, breast-shape guidance, sister sizing, sports bras and everyday bra-care advice in one place.

9Expert Guides
9Core Topics
2026Updated

Choose the Right Bra Fit Tool

Quick answers that help you move to the right calculator, guide or fit tool without duplicating the dedicated calculator page.

Which tool should I use to find my bra size?+
Start with the Bra Size Calculator if you can take an underbust and full-bust measurement. It is the site’s primary measurement-based sizing tool. If you cannot measure right now, the AI Smart Fit Calculator can help you narrow a starting range from fit questions instead.
Which tool should I use when my size changes by brand?
Use the Brand Size Decoder when your usual size fits differently across brands. Bra labels do not fully describe cup depth, wire width, band stretch or grading differences, so start from your measured size and use brand-specific fit information before changing sizes at random.
What should I use when the cups fit but the band does not?
Use the Sister Size Calculator. Sister sizing changes the band while keeping a similar cup volume, which is useful when the cup feels right but the band is too firm or too loose. The dedicated tool shows the adjacent options so you do not have to work them out manually.
Which tool helps if my bra spills, gaps or digs in?
Use the Bra Fit Problem Solver for symptom-based troubleshooting. It is designed for problems such as cup spillage, gaping, a riding band, digging straps or uncomfortable wires. For a deeper explanation of each symptom, open the Bra Fit Problems Guide.
Which tool should I use for US, UK or EU size conversion?
Use the Global Size Converter when you already know your size and need the equivalent label in another sizing system. If you do not know your starting size yet, calculate it first with the Bra Size Calculator, then convert only when shopping another regional system.
Where can I see the sizing method used by the calculator?
The dedicated Bra Size Calculator explains the measurement method beside the tool, including how band and cup results are derived and why the result should be treated as a starting size. Keeping the full methodology on that page helps avoid conflicting instructions across different tools and guides.
Where should I go if my size has changed over time?
Return to the Bra Size Calculator whenever your current bras no longer fit as expected or your body has changed. For pregnancy-related changes, use the pregnancy and postpartum sizing guide for more specific timing and fit considerations.
What should I do after I get a calculated size?
Treat the result as your starting point, then check how the band, cups, straps and wires sit in a real bra. If the size is close but not comfortable, use the Sister Size Calculator, Brand Size Decoder or Fit Problem Solver depending on what feels wrong.

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