轻测神器
心理测试、性格测试与趣味测试工具
洛克孵蛋百科
洛克王国世界玩家孵蛋助手
轻影神器
视频去水印、压缩处理工具
轻压神器
图片/视频/音频压缩
Bra Size Calculator
Free online bra size calculator that converts your measurements to the right cup and band size. Works with US, UK, EU, FR, and Asian sizing systems.
Bra Size Calculator
How to Measure
Size Chart
Your Measurements
Measure around the fullest part of your bust
Measure snugly under your bust
Measurement Tips
- Upper Bust: Lean forward 45° and measure around the fullest part of your bust
- Under Bust: Stand straight and measure snugly around your ribcage under the bust
- Keep the tape parallel to the floor for accurate results
- Measure without a bra or wear a thin unlined bra
- Take measurements 3 times and use the average
Step-by-Step Measurement Guide
What You Need
- A soft measuring tape (flexible cloth tape measure)
- A mirror to check your posture
- A comfortable environment where you can measure accurately
Step 1: Measure Your Under Bust (Band Size)
Stand straight with your arms relaxed at your sides. Wrap the measuring tape snugly around your ribcage, just under your bust. Make sure the tape is parallel to the floor all the way around. Record this measurement in centimeters.
Step 2: Measure Your Upper Bust (Over Bust)
Lean forward approximately 45 degrees so your back is parallel to the floor. Wrap the measuring tape around the fullest part of your bust. The tape should be loose enough to allow a finger to slide underneath but not too tight. Record this measurement in centimeters.
Step 3: Calculate Your Cup Size
Subtract your under bust measurement from your upper bust measurement. The difference determines your cup size:
Cup Size = Upper Bust - Under Bust
Common Cup Size Differences
| Difference (cm) | Cup Size |
|---|---|
| 10 cm | A Cup |
| 12.5 cm | B Cup |
| 15 cm | C Cup |
| 17.5 cm | D Cup |
| 20 cm | E / DD Cup |
| 22.5 cm | F Cup |
| 25 cm | G Cup |
| 27.5 cm | H Cup |
Important Notes
- Measurements may vary slightly between brands - always try on before buying
- Your bra size can change over time due to weight fluctuations, pregnancy, or hormonal changes
- Re-measure every 6-12 months or after significant body changes
- Different countries use different sizing systems - use our converter above
International Bra Size Comparison
This chart shows the equivalent band sizes across different international standards.
| EU / FR | International (cm) | US / UK (inches) | UK | Asia (JP/CN) |
|---|---|---|---|---|
| 65 | 65-67 | 28-29 | 30 | 70 |
| 70 | 68-72 | 30-31 | 32 | 75 |
| 75 | 73-77 | 32-33 | 34 | 80 |
| 80 | 78-82 | 34-35 | 36 | 85 |
| 85 | 83-87 | 36-37 | 38 | 90 |
| 90 | 88-92 | 38-39 | 40 | 95 |
| 95 | 93-97 | 40-41 | 42 | 100 |
| 100 | 98-102 | 42-43 | 44 | 105 |
Cup Size by Country
Cup sizes are generally consistent across countries, but some regions have slight variations:
| Cup | Difference (cm) | US/UK | EU | Asia |
|---|---|---|---|---|
| A | 10 | A | A | A |
| B | 12.5 | B | B | B |
| C | 15 | C | C | C |
| D | 17.5 | D | D | D |
| DD/E | 20 | DD/E | E | E |
| F | 22.5 | F | F | F |
| G | 25 | G | G | G |
| H | 27.5 | H | H | H |
Global Bra Size Statistics
即時結果 無需註冊 標準公式 免費使用
Bra Size Calculator: Stop Guessing, Find Your Perfect Fit in Seconds
Let’s be honest: buying a new bra is often a gamble. You grab a few sizes, head to the fitting room, and end up settling for one that’s “good enough.” Sound familiar? You’re not alone. The truth is, most people are wearing the wrong bra size. It’s not your fault. Sizing charts vary wildly between brands, and our bodies change over time. That’s where a reliable bra size calculator becomes more than just a tool—it becomes your personal fit expert.
This free online tool does one thing brilliantly: it takes two simple body measurements and instantly converts them into your correct cup and band size. No more guessing between a 34C or a 36B. What’s more, it works with US, UK, EU, FR, and Asian sizing systems, so you’re covered no matter where you shop. And because everything runs locally in your browser, you never have to worry about uploading personal photos or measurements. For anyone searching for a free bra size calculator that doesn’t require an app or sign-up, this is a game-changer.
Why Most Online Sizing Guides Let You Down (And This One Doesn’t)
You’ve probably tried following a brand’s size chart before. You measure, you check their table, and you still end up with a band that rides up or cups that gap. That’s because static charts can’t adapt to you. They give you a generic answer. A dynamic bra size calculator using centimeters and inches works differently. It calculates the actual difference between your under-bust and over-bust measurements to determine your exact cup volume.
The old way involves a lot of math and confusion: “If my under-bust is 75cm and my over-bust is 90cm, what size is that?” You’d have to subtract, find a chart, convert to inches, then find another chart for the brand’s country of origin. It’s exhausting. This tool eliminates all those steps. You simply enter your numbers, select your preferred standard (International, US, UK, or EU), and it does the complex conversion instantly. It’s like having a professional fitter right there with you.
How to Measure for a Bra at Home: The 3-Step Method
Before you use the calculator, you need two key numbers. Don’t worry—it’s quick and requires only a soft measuring tape. For the most accurate results, follow this how to measure bra size at home guide:
- Under Bust (Band Size): Stand up straight, relax your arms, and wrap the tape snugly around your ribcage, just under your bust. Keep the tape parallel to the floor. This is your band measurement.
- Upper Bust (Over Bust): Here’s the critical step most people miss. Lean forward about 45 degrees. This ensures you capture all your breast tissue. Wrap the tape around the fullest part of your bust. It should feel snug but not tight.
- Let the Calculator Work: Enter both measurements in centimeters. The bra size calculator will subtract the first from the second. The difference (e.g., 15cm) determines your cup size (C), while your under-bust determines your band.
A small tip: measure yourself three times and use the average. Also, always measure without a bra, or wearing a thin, non-padded one. If you’re wondering, is it better to measure bra size in cm or inches? — centimeters offer finer granularity, which leads to a more accurate cup calculation. This tool is optimized for cm, but it handles inch conversions seamlessly behind the scenes.
Understanding Your Results: Cup, Band, and Sister Sizes
Once you hit calculate, the tool presents much more than just a single size. You’ll see a clear breakdown:
- Your Bra Size: The final recommended size (e.g., 75C or 34B).
- Cup Size & Band Size: Shown separately for clarity.
- Cup Difference: The exact numeric difference between your two measurements.
This transparency is crucial. Maybe you receive a result of 80D but the band feels tight on the loosest hook. That’s where bra sister sizes come in. Sister sizes are alternate fits that hold the same cup volume. For example, if 80D is snug, you could try 85C (going up a band, down a cup). Or if 80D feels loose, try 75E (down a band, up a cup). The calculator generates these alternatives for you automatically, saving you from returning online orders.
Privacy First: Why This Online Bra Size Calculator Is Completely Safe
Let’s address the elephant in the room. Many people hesitate to use a free online bra size calculator because they worry, “Will my measurements be stored or shared?” It’s a valid concern. Your body data is personal.
Here’s what sets this tool apart: it’s 100% client-side. That means all the calculations happen right inside your web browser, whether you’re on Chrome, Firefox, or Safari. Your measurements never touch a server. They never cross the internet. You don’t need to create an account, log in, or give your email address. When you close the tab, all data disappears. For anyone needing a privacy-friendly tool to calculate bra size without uploading photos, this is the definition of secure. You get the results you need with zero risk.
International Size Conversion: From US to UK to EU
One of the most frustrating aspects of bra shopping is the inconsistency between countries. A 34C in the US is not the same as a 34C in France or Japan. This tool includes a full international bra size conversion chart as part of its output. After calculating your size in your preferred standard, it automatically shows you the equivalent sizes for:
- US/UK (based on inches)
- EU/FR (based on centimeters)
- Asia (JP/CN) (common for online retailers like Shein or Zalora)
So if you find a beautiful French brand online, you can immediately see that your US 34B converts to a 90B in their system. No more manual guesswork or returns due to wrong sizing.
Stop Settling for “Good Enough”
You deserve a bra that fits from the moment you put it on. One that doesn’t dig into your shoulders, ride up your back, or require constant adjustment. The journey starts with two simple measurements and a tool you can trust. Whether you’re shopping for a new everyday t-shirt bra, a sports bra for running, or a special occasion piece, use this bra size calculator first. Know your real size. Then, shop with confidence, no matter which country’s sizing system a brand uses. It’s free, it’s private, and it takes less than two minutes. Give it a try—you might be surprised by what you discover.
Frequently Asked Questions about Bra Size Calculator
How accurate is an online bra size calculator compared to a professional fitting?
A professional fitting at a store is still great, but studies have shown that at-home measurements, when done correctly, are just as accurate. The key is following the lean-forward method for the upper bust. This calculator uses the standard industry formula (difference in cm = cup size), which is the same one professionals use. The main advantage here is that you can re-measure yourself anytime, for free, without scheduling an appointment.
What if my measurements fall between two cup sizes?
This happens more often than you might think. For example, if your under-bust is 75cm and your over-bust is 88.5cm, the difference is 13.5cm. The calculator will show you the nearest standard cup (closer to a B, as 12.5cm is a B). The results section also includes “sister sizes,” which provide the next best alternative fits. We also recommend trying both the calculated size and its closest sister size when you go shopping.
Can men use this calculator for gynecomastia or chest measurement?
Yes, absolutely. The bra size calculator works based on the physical difference between two circumferences. It doesn’t assign gender. It simply provides the size that corresponds to the measurements entered. Many men seeking support for gynecomastia use this tool to find comfortable bralettes or compression garments. The same privacy and accuracy rules apply.
Why do I get a different size from one brand to another?
Brands often use different “vanity sizing” or have unique fits for their target markets. That’s why this calculator provides the standard size based on international agreements. Always use the result as your starting point. Read the brand’s specific size guide (they often recommend going up or down a cup). The conversion table within the tool helps you navigate these differences by showing you the raw band equivalent across systems.
Is there a mobile-friendly version or app I need to download?
No app or download is required. This online bra size calculator works perfectly on any smartphone, tablet, or computer. It’s a progressive web tool, meaning you can even add the page to your phone’s home screen for quick access. Unlike heavy apps, it won’t drain your battery or ask for unnecessary permissions. It’s simply a fast, lightweight page you can use anywhere, even in a fitting room.
How often should I remeasure my bra size?
A good rule of thumb is every 6 to 12 months. However, you should remeasure after any significant body change: weight fluctuation (gain or loss of more than 5-7 kg), pregnancy, breastfeeding, or starting a new fitness routine. Hormonal changes during your menstrual cycle can also temporarily affect your size. Many regular users keep the calculator bookmarked and check their size twice a year, just like changing their smoke detector batteries.