究極のブラジャーのサイズ変換 & 製造基準ガイド

Inconsistent bra sizing is a major cause of high return rates, directly impacting profit margins for apparel brands. The lack of a universal sizing standard across US, 英国, 欧州連合, and Asian markets creates confusion, supply chain errors, and brand reputation issues.

Discover how to optimize your sizing system, reduce returns, and enhance customer loyalty. This guide explores key strategies like 3D scanning and custom size charts, helping you navigate global sizing challenges and improve fit accuracy for better business outcomes. Keep reading to learn more.

An Analysis of Global Bra Size Standards

Global bra sizing systems are inconsistent, leading to significant challenges in both e-commerce and manufacturing. The main issue lies in the treatment of band and cup sizes:

• Band Sizes: These measure the rib cage circumference and are relatively uniform across most regions, offering straightforward conversions.

• カップサイズ: These differ significantly between markets. 例えば, a US DD does not equate to a UK DD, as different regions use incompatible volume calculations and letter systems. This discrepancy creates confusion, especially in inventory management and customer communication.

The lack of a unified sizing standard complicates global trade. Businesses must maintain multiple sizing charts, leading to inefficiencies, especially with larger cup sizes where discrepancies increase. Relying on third-party tools to bridge these gaps places the translation burden on both retailers and customers, raising return rates and operational challenges.

How to Read a Bra Size Chart for Different Markets

Fragmented global sizing standards create operational challenges for manufacturers and e-commerce businesses. Accurately interpreting size charts helps avoid the following issues caused by these discrepancies:

• US and UK standards use an inch-based system where the band number (例えば。, 34, 36) does not directly equal the physical measurement in inches.

• The European (欧州連合) system uses a direct metric correlation. An EU 75 band size corresponds directly to a 75-centimeter back circumference, making it a more literal and less abstract standard. This discrepancy is a primary source of error when converting sizes for international supply chains.

Cup Size Conversion Inconsistencies

Cup size conversions fail because different markets use unique letter progressions and growth increments.

• Letter Progression: European systems use a simple alphabetical sequence (a, b, c, d, e, F) but often use 2cm increments instead of the one-inch standard common in the US/UK. For larger volumes, they may use letters like K, L, and M that have no direct US/UK equivalent.
• US vs. UK Systems: While band sizes are the same, cup letter progressions diverge after D. A UK 34G is not the same as a US 34G; understanding the different labeling (例えば。, UK double letters) is essential for accurate inventory management.
• Amplified Discrepancies: The mathematical differences between sizing charts are most significant in D+ cups. A one-size error in an A or B cup is minor, but the same error in a G or H cup can represent a substantial volume mismatch, leading to high return rates.

Finding Your Bra Size Without a Tape Measure

Follow these steps for a more accurate fit:

ステップ 1: Use an Existing Bra as a Baseline

Start with your best-fitting bra. The size printed on the tag provides key information about the regional sizing system it follows, such as US, 英国, or European standards. Since each region uses different measurement methods, identify which system your bra follows to ensure accurate comparisons later.

ステップ 2: Assess the Band Fit

The band measurement is the most reliable part of your size, as it remains consistent across different systems. A well-fitted band should sit snugly and level across your back, parallel to the floor. If the band rides up or feels loose, it’s a sign you need a smaller size. This is the first adjustment to make when determining your fit.

ステップ 3: Understand Cup Volume Differences

Cup sizes differ significantly across regions and brands. 例えば, a US DD cup doesn’t match the volume of a UK DD cup. Since there’s no universal standard, it’s essential to consult brand-specific size charts. These charts provide the most reliable way to accurately convert cup sizes across various systems and ensure a proper fit.

The Sister Size Concept and Its Impact on Sizing

Sister sizing helps manage fit variations across different global sizing systems by ensuring consistent cup volume when band sizes change. Here’s how it works:

Cup volume is relative to the band size, which creates an inverse relationship between the band number and cup letter.

• When the band size decreases, the cup letter increases to maintain the same volume: 34C = 32D (the cup volume remains the same, but the band size is smaller).

• Conversely, when the band size increases, the cup letter decreases to preserve the same volume: 34C = 36B (the band is larger, but the cup volume is the same).

In retail, sister sizing helps sales associates offer alternatives when a customer’s ideal size is out of stock, improving inventory flexibility and customer experience. For e-commerce, it supports online fit calculators and size conversion tools, simplifying international sales without requiring excessive stock for every size variation.

Why Bra Size Calculators Don’t Work for Adhesive Products

Standard bra size calculators fail for adhesive bras because they are based on a band-to-cup ratio, which doesn’t apply to bandless garments. These calculators measure cup volume by comparing the underbust and overbust, but adhesive bras rely on surface adhesion, not on a support band or cup volume. The fit depends on the breast’s shape, 音量, and the surface area available for adhesion.

Adhesive bras function differently from traditional bras, which provide structural support using band and cup measurements. For this reason, most adhesive bra manufacturers create their own sizing charts, as traditional calculators are not suitable for these products. For a complete and detailed sizing guide, check out Xinke’s adhesive bras with our proprietary size charts, tailored for a perfect fit.

Standardizing Cup Depth with 3D Scanning Technology

3D scanning technology captures precise anatomical data, bypassing the inconsistencies of regional sizing standards. By replacing traditional letter designations with quantifiable metrics for cup volume, it creates a universal fit standard that simplifies manufacturing and reduces e-commerce friction.

This data-driven approach aggregates large-scale 3D measurements to build a global sizing framework based on actual body geometry. Algorithms predict optimal fit, eliminating the reliance on flawed third-party conversion tools used in international markets.

The result is a unified standard that enhances consistency across supply chains. For manufacturers, 3D scanning provides exact digital models for production, ensuring products with a given size code are consistently produced worldwide.

Reducing Returns with Accurate Sizing Labels

Here’s a comparison table to help navigate the key differences in band and cup sizes across major global markets, including the US, 英国, and EU. This guide simplifies sizing conversions for international shopping and inventory management.

How to Create a Custom Bra Size Chart for Your Brand

Creating a custom bra size chart ensures a better fit for your customers and reduces returns. Here’s how to build one for your brand:

Establish Your Base Sizing System

Choose a regional standard (US, 英国, or EU) for your brand’s sizing. This defines your measurement units: centimeters for EU and inches for US/UK. This decision guides all future sizing decisions.

Define Measurement Protocols

Set consistent methods for measuring customers. The band is measured snugly under the bust, while the bust measurement is taken at the fullest part of the chest. To calculate cup size, use the formula:
Bust Measurement – Band Measurement = Cup Differential
(1 inch = A cup, 2 inches = B cup, 等).

Map Measurements to Your Sizing Logic

Convert raw measurements into band sizes and assign cup sizes based on the band-bust differential. 例えば, an underbust measurement of 73-77 cm becomes EU 75. Incorporate sister sizing to provide alternatives (例えば。, 32D = 34C = 36B).

Integrate International Conversion

To serve global markets, add conversions for major regions (US, 英国, 欧州連合, Australia). Since cup sizes differ between systems, ensure you show both centimeter and inch equivalents and clarify discrepancies.

Validate with Fit Model Testing

Real-world testing is key. Fit models across your full size range, paying close attention to larger cup sizes where discrepancies are common. Adjust your chart based on feedback to ensure it matches real-world fits.

結論

Creating a clear, standardized sizing system is fundamental for any lingerie brand. By understanding global size variations and leveraging technology, you can develop accurate custom charts that reduce costly returns. This consistency builds customer trust and streamlines your international sales process.

Review your brand’s current size chart to identify gaps or inconsistencies. If you’re looking to develop a sizing system tailored to your product line, including our innovative silicone adhesive bras, シンケ R&D team can guide you through the process.

Get in touch with us to create a reliable, accurate sizing model that suits both your brand and your customers.

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