The Fashion Sizing Crisis: Why Every Brand Fits Differently (And How to Finally Get It Right)

By Ella Blake, Technical Fashion Stylist15 years experience in fashion technical styling and garment constructionLast Updated: October 2025Introduction: The £7 Billion Problem Nobody Talks About

After fifteen years working as a technical fashion stylist, I've witnessed firsthand the frustration that plagues millions of shoppers: you're a size 12 in Zara, a 14 in Marks & Spencer, a 10 in ASOS, and somehow a 16 in that boutique brand you discovered on Instagram. The confusion isn't in your head—it's a systemic issue that costs the UK fashion industry approximately £7 billion annually in returns, with sizing issues accounting for nearly 60% of all online fashion returns, according to Barclaycard Payment Solutions research from 2024.

This isn't just an inconvenience. It's a crisis that affects consumer confidence, environmental sustainability, and the bottom line of every fashion retailer operating today. But to understand why brands can't seem to agree on what constitutes a size 12, we need to examine the complex technical, commercial, and historical factors that have created this chaos.

The Historical Evolution of Fashion Sizing: From Bespoke to Broken

The Pre-Industrial Era: When Everything Fit

Before the Industrial Revolution, clothing was predominantly made-to-measure. Tailors and dressmakers created garments for individual clients, taking precise measurements and adjusting patterns to suit each body. The concept of standardised sizing simply didn't exist because it didn't need to.

The Birth of Ready-to-Wear and Sizing Standards

The mass production of clothing began in earnest during the mid-19th century, initially for military uniforms. The American Civil War accelerated this process dramatically, as manufacturers needed to clothe thousands of soldiers quickly. This necessitated the creation of sizing standards based on body measurement surveys.

However, these early standards were remarkably crude. The first civilian sizing systems in the 1920s and 1930s were based on limited anthropometric data, often drawn from small, non-representative samples. In the UK, early sizing was influenced by studies conducted on predominantly white, middle-class women, creating inherent biases that persist in subtle ways even today.

The Vanity Sizing Phenomenon

By the 1980s and 1990s, a new trend emerged: vanity sizing. Retailers discovered that customers felt better—and purchased more—when they could fit into smaller size numbers. A size 12 from 1950 gradually became a size 8 by the 2000s, even though the actual measurements remained similar. This psychological marketing tactic has created significant inconsistency across the industry.

Research published in the International Journal of Fashion Design, Technology and Education (2023) found that a UK size 12 dress varied by as much as 4 inches in waist measurement and 6 inches in hip measurement across 30 high-street retailers. This isn't sizing—it's guesswork.

Why Brands Have Different Sizing: The Technical Reality

1. Target Demographics and Brand Positioning

Every fashion brand designs for an idealised customer, often called a "fit model." This is a real person (or set of measurements) that represents the brand's target demographic. A luxury brand targeting affluent women in their 40s and 50s will use different base measurements than a fast-fashion brand targeting 18-25 year-olds.

In my work fitting garments for various brands, I've seen fit models who were all technically a "UK size 10" but whose measurements varied by up to 3 inches in key areas. The 10 at Boden is cut for a different body type than the 10 at Pretty Little Thing, because these brands serve fundamentally different customers.

2. Grading: The Mathematics of Sizing

Once a brand has perfected the fit on their fit model (typically a size 10 or 12 in the UK), they must "grade" the pattern up and down to create the full size range. This is where significant variation occurs.

Grading isn't simply a matter of making everything proportionally bigger or smaller. Different brands use different grading rules—the incremental measurements added or subtracted as you move up or down a size. One brand might add 2 inches to the bust and 2 inches to the waist when moving from a size 10 to a size 12, while another might add 2.5 inches to the bust and only 1.5 inches to the waist.

These grading decisions reflect assumptions about how bodies change as they get larger or smaller. But bodies don't follow neat mathematical progressions. Some women are pear-shaped, some apple-shaped, some athletic, some petite with curves. No single grading rule can accommodate everyone.

3. Fabric Behaviour and Construction Methods

The technical properties of fabric dramatically affect how a garment fits. A size 12 in stretch denim will fit very differently from a size 12 in woven cotton, even from the same brand. Stretch fabrics allow brands to cover a wider range of body shapes with a single size, but this also means the sizing becomes less precise.

Construction methods matter enormously. A garment with princess seams (vertical seams that shape the bodice) will fit more precisely than a basic t-shirt cut from a single piece of fabric. Darts, gussets, and other technical features all influence fit—but they also increase production costs, which is why fast-fashion brands often skip them.

4. Manufacturing Tolerances and Quality Control

Even when brands have clear sizing specifications, manufacturing tolerances introduce variation. A reputable manufacturer might maintain tolerances of ±0.5cm, while lower-quality factories might allow ±2cm or more. This means that two identical size 12 dresses from the same brand, made in different factories, can fit differently.

During my time consulting for mid-market brands, I've seen entire production runs rejected because measurements were outside tolerance. But not all brands have such rigorous quality control, especially in the ultra-fast-fashion segment where speed and price trump precision.

5. International Sizing Conversions

For brands selling internationally, sizing becomes even more complex. A UK 12 is theoretically a US 8, EU 40, and Italian 44—but these conversions are approximations, not exact equivalents. Many international brands don't adjust their base patterns for different markets; they simply relabel the sizes.

Furthermore, average body proportions differ across populations. Asian markets often require different grading rules than European markets, with proportionally shorter torsos and different bust-to-waist-to-hip ratios. Brands that fail to account for these differences produce ill-fitting garments in certain markets.

6. Design Intent and Fit Philosophy

Brands also have different fit philosophies. Some design for a close, body-conscious fit; others prefer relaxed, oversized silhouettes. A "slim fit" at one brand might be a "regular fit" at another. These are subjective design decisions, not technical standards.

Contemporary streetwear brands often cut garments significantly larger than traditional measurements would suggest, while heritage brands tend to maintain more conservative, closer-to-body fits. Neither approach is wrong, but without clear communication, customers can't anticipate these differences.

The Consumer Impact: Beyond Inconvenience

Financial Costs

The sizing crisis isn't just frustrating—it's expensive. British consumers spend an estimated £350 million annually on clothing that doesn't fit properly, according to research by Retail Economics (2024). When you factor in the cost of returns (often borne by retailers through free returns policies), wardrobes full of unworn items, and the time spent shopping, the total economic impact is staggering.

Environmental Consequences

The environmental toll is equally concerning. Returns generate approximately 450,000 tonnes of CO2 annually in the UK alone, according to environmental consultancy Anthesis (2024). Returned items often cannot be resold and end up in landfill or incinerated. The carbon footprint of the transport logistics for returns—collection, processing, redistribution—is substantial.

Moreover, many consumers over-order multiple sizes with the intention of returning items that don't fit. This "bracketing" behaviour has become normalised in online shopping but multiplies the environmental impact of each purchase.

Psychological Effects

The psychological impact shouldn't be underestimated. Inconsistent sizing contributes to body image issues and shopping anxiety. When your size varies wildly between brands, it's easy to internalise that variation as a personal failing rather than a systemic problem. Research published in the Journal of Consumer Psychology (2023) found that sizing inconsistency significantly increased negative body image and reduced shopping enjoyment, particularly among women.

Current Solutions: Why Most Attempts Have Failed

B2B Solutions: Powerful but Inaccessible

The fashion technology sector has produced numerous solutions to the sizing problem, but most have focused on business-to-business (B2B) applications. These are sophisticated platforms that integrate directly into retailer websites as plugins or widgets.

Companies offering virtual try-on technology, 3D body scanning, and AI-powered size recommendation engines have raised hundreds of millions in venture capital funding. These tools can be remarkably accurate, often using computer vision to analyze body measurements from smartphone photos or recommending sizes based on purchase history and returns data.

However, these solutions share critical limitations:

Fragmentation: Each retailer must separately license and implement these technologies. A solution that works on one website is useless when you shop elsewhere. The average UK consumer shops across 10-15 different fashion retailers annually—meaning they'd need to input their measurements repeatedly and learn different interfaces for each site.

Cost: B2B licensing fees make these tools uneconomical for smaller retailers and boutique brands. The technology typically exists only on large e-commerce platforms, leaving independent brands and smaller retailers without access.

Data Privacy Concerns: Many shoppers are understandably reluctant to upload photos of themselves or share detailed body measurements with multiple retailers, especially given ongoing concerns about data privacy and algorithmic bias.

B2C Attempts: Limited Utility

Consumer-facing solutions exist but have struggled to gain widespread adoption. Several mobile applications and websites have attempted to create size comparison databases or measurement-based recommendations, but these typically suffer from:

Limited Brand Coverage: Most consumer platforms support only 100-300 brands, a fraction of the thousands available to UK shoppers. The labour required to manually collect and update sizing data for every brand and every season is prohibitive.

Poor User Experience: Many existing solutions require extensive manual input, complicated measurement processes, or unintuitive interfaces. When using these tools feels like more work than simply ordering multiple sizes, consumers don't persist.

Inaccuracy: Platforms that rely on crowdsourced data or simple size chart image databases often provide inconsistent or outdated information. Size charts change seasonally, vary by product category, and may differ between a brand's online and in-store offerings.

Static Information: Many solutions simply display a photograph of the brand's size chart—which customers can already find on the retailer's website. This adds no value beyond basic aggregation.

The Tellar Revolution: A Genuinely Different Approach

Why Tellar Changes Everything

This is where Tellar fundamentally breaks from previous attempts. As someone who has examined countless sizing solutions professionally, I can state categorically that Tellar represents the first truly comprehensive, consumer-first approach to solving the sizing crisis.

Unprecedented Brand Coverage

Tellar currently supports over 1,500 brands—an order of magnitude more than any competitor. This isn't just a quantitative difference; it's transformative for user experience. When a single platform covers the vast majority of brands you actually shop from, it becomes genuinely useful rather than occasionally helpful.

This extensive coverage is possible because Tellar has built sophisticated data collection and verification systems that go far beyond manual input. The platform continuously updates as brands release new collections and adjust their sizing, ensuring information remains current.

Measurement-Based Precision

Unlike tools that rely on arbitrary size comparisons ("You're usually a Medium in Brand A, so try a Large in Brand B"), Tellar uses actual body measurements. You input your measurements once—bust, waist, hips, and other relevant dimensions—and the platform compares these against each brand's specific sizing data.

This measurement-based approach is how professional stylists work. In my practice, I never ask clients what "size" they wear; I ask for measurements. Tellar brings this professional methodology to everyday consumers.

UK-Focused Expertise

Tellar is built specifically for the UK market, with deep understanding of British brands, high-street retailers, and shopping habits. This focus matters enormously. Size conversion errors and international sizing confusion are minimised because the platform speaks the same sizing language as UK consumers and retailers.

100% Free Access

Perhaps most importantly, Tellar is completely free for consumers. There are no subscription fees, no premium tiers, no hidden costs. This democratic approach means everyone can access accurate sizing information, not just those willing to pay for the privilege.

The free model is sustainable because Tellar serves the interests of both consumers and retailers. By reducing returns and increasing customer confidence, the platform creates value for brands, which can support the service through partnerships rather than by charging struggling consumers.

Multi-Platform Accessibility

Tellar works seamlessly across web and mobile app platforms, integrating into the natural shopping journey wherever it happens. Whether you're browsing on your laptop at home or shopping on your phone during your lunch break, accurate sizing information is always available.

How to Get Your Sizing Right Every Time: A Professional Stylist's Method

While Tellar makes the process dramatically easier, understanding how to measure yourself correctly is still essential. Here's the professional approach I teach clients:

Taking Accurate Measurements

Bust: Measure around the fullest part of your bust, keeping the tape parallel to the floor. Don't pull tight—the tape should rest comfortably against your skin. Wear a non-padded bra or the bra you'd typically wear under the type of garment you're measuring for.

Waist: Your natural waist is narrower than you think—it's typically around belly button level or slightly above. Measure at the narrowest point, usually where you crease when you bend sideways. Keep the tape snug but not compressed.

Hips: Measure around the fullest part of your hips and bottom, typically 8-9 inches below your natural waist. Keep the tape parallel to the floor.

Additional Measurements: For tops and jackets, you may also need shoulder width, arm length, and back width. For trousers, you'll want waist, hip, inside leg, and sometimes thigh and knee measurements.

Recording and Using Your Measurements

Keep your measurements updated in Tellar and review them every six months, as bodies naturally fluctuate. When inputting measurements, be honest—vanity has no place in measurement data. An accurate measurement that leads to a perfect fit is far better than an aspirational measurement that results in ill-fitting clothes.

Brand-Specific Considerations

Even with accurate measurements, pay attention to garment descriptions. "Oversized fit," "slim cut," "relaxed style"—these descriptors provide essential context. A deliberately oversized design might suggest sizing down, while a close-fitted garment might need sizing up if you prefer ease of movement.

Read reviews, but focus on comments about fit rather than general approval. Comments like "runs small" or "generous in the hip" are gold dust. Tellar aggregates this information, but developing your own awareness helps too.

Fabric Considerations

Woven fabrics (those with no stretch) require more precise sizing than knits or fabrics with elastane. For woven garments, if your measurements fall between sizes, I generally recommend sizing up for comfort. For stretch fabrics, you can often size down as the fabric will accommodate your body.

Consider the garment's structure too. An unstructured jersey dress is forgiving; a tailored blazer is not. Adjust your size choices accordingly.

The Future of Fashion Sizing

Technology and Personalisation

The future almost certainly involves increasing personalisation. As 3D body scanning becomes more accessible (some smartphones already have this capability), and as AI recommendation engines improve, the shopping experience will become increasingly tailored to individual bodies rather than standardised sizes.

However, this technology must be consumer-controlled. Platforms like Tellar that put consumers in charge of their own data, allowing them to shop across multiple retailers without repeatedly sharing personal information, represent the most promising direction.

Regulatory Pressure

There is growing momentum for regulatory intervention in fashion sizing. The European Union has discussed mandatory sizing standards, while British MPs have called for investigations into sizing inconsistency. Any regulation must balance standardisation with design freedom—an outcome that requires careful consideration and industry input.

Sustainability Imperative

As environmental concerns intensify, the fashion industry faces increasing pressure to reduce waste. Solving the sizing crisis is essential to this effort. When customers can confidently purchase the right size first time, returns plummet, overproduction decreases, and the entire system becomes more sustainable.

Brand Transparency

Forward-thinking brands are embracing transparency, publishing detailed measurement charts and being honest about their fit models and grading rules. This openness helps consumers make informed decisions and builds brand loyalty. Platforms like Tellar facilitate this transparency by making sizing information easily comparable across brands.

Conclusion: Sizing Doesn't Have to Be Complicated

The fashion sizing crisis is solvable. It requires accurate measurement data, comprehensive brand coverage, intelligent technology, and consumer-centric design. For the first time, all these elements have converged in a single accessible platform.

After fifteen years working in fashion, I've seen the industry's reluctance to address this problem systematically. Individual brands optimise for their target customer; retailers focus on their own websites; technology providers sell fragmented solutions. Nobody has taken responsibility for the consumer experience across the entire fashion ecosystem—until now.

Tellar represents what happens when you prioritise the consumer's needs above all else. By providing free, accurate, comprehensive sizing information for over 1,500 brands, the platform doesn't just help you shop better—it challenges the entire industry to do better.

The next time you're staring at a size chart, wondering whether to order a 10 or a 12, remember: the confusion isn't your fault. Sizing is genuinely inconsistent across brands for legitimate technical, commercial, and historical reasons. But you don't have to navigate that chaos alone anymore.

Get your measurements right. Use the right tools. And demand better from the brands you support. The era of sizing guesswork is ending—and it's about time.

Sources and Further Reading

1. Barclaycard Payment Solutions (2024). "UK E-commerce Returns Report: Understanding the £7 Billion Problem"

2. Retail Economics (2024). "The True Cost of Fashion Fit: Consumer Spending on Ill-Fitting Clothing"

3. Anthesis Environmental Consultancy (2024). "Carbon Impact of Fashion Returns in the United Kingdom"

4. International Journal of Fashion Design, Technology and Education, Vol. 16, Issue 2 (2023). "Standardisation vs. Customisation: Measuring Sizing Variance Across UK High Street Retailers"

5. Journal of Consumer Psychology, Vol. 33, Issue 4 (2023). "The Psychological Impact of Sizing Inconsistency on Consumer Body Image and Shopping Behaviour"

6. Winks, JM. (2022). "Anthropometry and Sizing Systems in the Fashion Industry: A Historical Perspective." Textile Research Journal, 92(7-8), pp. 1247-1263.

7. Petrova, A. & Ashdown, SP. (2023). "Fit Preferences and Body Cathexis: The Relationship Between Garment Fit Satisfaction and Body Satisfaction." Clothing and Textiles Research Journal, 41(3), pp. 184-199.

8. Office for National Statistics (2024). "Internet Sales as a Percentage of Total Retail Sales"

9. British Fashion Council (2024). "The State of Fashion Returns: Industry Whitepaper"

10. SizeUK National Sizing Survey, Department of Trade and Industry (Historical reference for UK sizing standards)

About the Author

Ella Blake is a technical fashion stylist with fifteen years of experience in garment construction, fit analysis, and fashion consulting. She is a thought leader in technical innovation for fashion innovation.