The Easiest Way to Reduce Returns? Just Publish the Measurements.
Every time I buy G-Star jeans, it's the same routine. The size guide gives me two numbers: waist and inside leg. Nothing about whether that waist figure is the exact garment measurement or includes ease. So I do what most customers do when a brand won't tell them what they need to know, I order two sizes and send one back.
Compare that to COS. Known for a boxy, oversized fit, but the size guide doesn't mention that at all. Instead it asks for your weight, age and body shape, then tells you what size it thinks you should buy. I know COS sizing runs large, so I ignore the recommendation entirely and order two different sizes smaller than whatever it suggests.
Two different brands, two different approaches, one identical result: the customer can't make a confident decision, so they order multiple sizes and return what doesn't work. Multiply that by every customer who doesn't have insider knowledge of how a brand fits, and you've got a returns problem that has nothing to do with the product and everything to do with the information gap.
Why the usual fixes don't close the gap
Most brands try to solve fit uncertainty with better photography, a size chart based on body measurements, or a quiz like COS's. All three have the same flaw: they tell the customer about themselves, not about the garment. But a customer doesn't need help understanding their own body — they need to know what the piece of clothing actually measures, so they can compare it to something they already own that fits the way they want.
The fix is simple, and brands already have the information
You don't need a sizing algorithm. You need a flat measurement chart, with a matching illustration showing exactly where each measurement is taken, sitting on the product page next to the size chart you already publish. Then tell the customer, in a line or two, how to measure themselves and compare: lay the garment flat, smooth out the wrinkles, and measure at the points shown.
What this actually does for returns
A customer who can compare a garment's real measurements to a jumper already hanging in their wardrobe doesn't need to guess, doesn't need to order two sizes as insurance, and doesn't need a quiz to tell them what a brand thinks they should buy. They can just check. That's the whole fix, no new technology, no investment, just information the brand already has, put where the customer can use it.
Some fabrics and fits make this trickier — very stretchy jersey, bodycon styles, anything where the finished measurement isn't the whole story. That's a separate conversation. But for the bulk of what brands sell, this approach alone would meaningfully cut returns.
If you're a brand still relying on body-measurement charts or a fit quiz, the question worth asking isn't "how do we get customers to trust our size guide." It's "why aren't the garment's measurements on the page yet?"