Ask most retail teams why they carry a wider size range and the answer usually arrives in the language of brand values, whether that’s representation, inclusion or doing the right thing. That instinct is sound, but it has quietly obscured a more commercial truth. Size range has become one of the clearest levers a retailer can pull on returns, repeat purchase and lifetime value, and the businesses treating it that way are protecting margin their rivals are giving away.
Where the margin leaks
Start with returns, because that’s where the money leaks. In the UK, around 30% of online fashion purchases are sent back each year, and poor fit is the single biggest reason shoppers give. The problem skews female with nearly 13% of women citing poor fit as a regular reason for returning, against 7% of men. Add in bracketing, where 62% of shoppers now order several sizes intending to keep one, and you have a reverse-logistics bill that swallows the margin on the sale that did stick.
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None of this is cheap to absorb. Industry estimates put the value of returned online purchases at roughly a fifth of everything sold, with a global cost measured in the hundreds of billions, which is why retailers have been urged to invest in true sizing technology. Every returned parcel carries the cost of outbound and inbound shipping, handling, inspection, repackaging and, often, markdown or write-off. A sale that comes back is worse than a sale never made.
The root of it is how ranges are built. Plenty of retailers treat sizing as an afterthought, grading a core collection up and down a narrow band and hoping it covers enough of the market. When the range is shallow, especially at the ends of the size curve, a large share of shoppers either can’t buy at all or settle for something close enough that they’ll probably send it back. Fit and range are the same problem wearing two labels.
Building around fit
A smaller group of retailers work the other way round, starting from fit and range rather than adding them later. Category specialists are the clearest example, because the whole proposition depends on getting fit right. In lingerie, where the margin for error can be a single cup size, that shows up in the depth of the offer. Responding to customer demand the mainstream leaves unmet, several fit-led specialists now carry sizing well beyond the high-street norm, running deep into the fuller-bust range with back sizes into the 40s, all supported by fit guides and size tools built into the buying journey. The breadth matters less on its own than what it removes, namely the fit failures that generate returns in the first place.
Service does the same quiet work. A retailer that steers a shopper to the correct size before the order ships removes the most common trigger for a return, at a fraction of the cost of processing one. Shoppers agree, naming better sizing guidance, more consistent sizing across products and clearer reviews as the changes most likely to make them return less.
Fewer returns, more loyalty
The payoff starts with reach. The global plus-size clothing market was worth around $294bn in 2024 and is forecast to reach roughly $445bn by 2032, with more than half of women in some markets now wearing what the trade still labels plus size. That’s a large base of customers a narrow range simply can’t serve, and it feeds a wider argument for retailers to move beyond the average customer when they plan an assortment.
From there the effects compound, as a shopper who finds a real fit is more likely to buy again, more likely to pay full price, and less likely to hedge with bracketing next time. Retention is where the maths gets compelling, because holding on to an existing customer costs a fraction of winning a new one, and a well-fitted first purchase is the surest route to a second. Fewer returns cut the cost to serve, higher repeat rates lift lifetime value, and the effective cost of acquisition falls because you’re not paying twice to win back a customer who left because nothing fit. Range depth, put simply, shows up in several lines of the P&L at once.
Getting execution right
None of this is automatic since extending a range ties up working capital in stock that has to sell through, and depth at the edges of the size curve carries markdown risk if buying isn’t disciplined. Consistency matters too, because a wider range that still fits unpredictably won’t move the returns needle. The retailers seeing the benefit pair range with accurate fit guidance, consistent grading and clear product information, so the extra choice converts rather than clogs the returns lane.
For retail leaders, the reframe is the useful part. Size range doesn’t need defending as a values project competing for budget against commercial priorities. Handled well, it is a commercial priority, a lever on returns, conversion, loyalty and margin that happens to be inclusive too. The retailers who work that out first will keep the customers, and the profit, that the rest hand back at the returns desk.
About the author: Annie Button is a freelance writer based in the UK. She specialises in business development, sustainability, digital trends, marketing, and HR.
