This is just one example of the sizing issues that still plague fashion retail on the high street.

Naturally, ecommerce makes things all the more confusing, because if shoppers don’t know what size they’ll be in one store to the next – how are they meant to know what size to order online?

Unsurprisingly, size and fit remains a big issue for ecommerce retailers, with consumers unable to try on items, and wrong-size purchases contributing to high return rates.

There are ways to combat the problem, however. One strategy is online sizing guides, which can help consumers to find the right fitting clothes and shoes. As well as offering functional value, size guides can be both fun and interactive, which can also help to enhance the user experience.

With this in mind, we’ve rounded up some of the best online size guides out there, together with the reasons why they work so well.


Uniqlo doesn’t use typical UK sizing, e.g. size 8, 10 etc. for women. Instead, it uses a ‘small, medium, large’ structure (alongside measurements in inches and centimetres) for both sexes.

This can make things trickier for shoppers, which is why Uniqlo includes a guide that explains its measurements in comparison to standard sizing. But even this does not mean a good fit is guaranteed.

Consequently, Uniqlo also uses Fit Finder technology to help shoppers find their ‘perfect fit’. It involves an interactive guide, which asks shoppers a few key questions to help narrow down to a size.

uniqlo size guide

After entering height and weight, it asks about belly shape (and hip shape for women) – which is an unexpected but ingenious little detail. The illustrations add a quirky element, bringing to life physical differences.

belly shape

Moving forwards, the guide then asks for additional information like height, and how you usually like clothes to fit.

The latter question is particularly clever, as it recognises that individual taste and preference can impact on what size you should choose. This brings in an element of personalisation, hinting that not everyone likes their clothes to fit in the same way.

uniqlo fit preference

Eventually, the guide recommends what size to purchase, based on the information you entered plus info from thousands of similar shoppers. While I’ve not yet bought anything based on the guide, if it’s as functional as it is easy and enjoyable to use, it’s likely to be valuable.

uniqlo best fit


The issue of size is not quite as complex for footwear retailers as it is for fashion. After all, most feet are pretty similar in size and shape, with the issue usually extending to whether the shoe itself comes up slightly snug or a little loose.

However, Aldo ensure that shoppers know this kind of information before ordering, using True Fit technology to determine how a shoe might fit.

aldo size guide

Interestingly, it does this by comparing its items with an existing pair of your favourite shoes. For example, if you live and die in Converse, you can select this brand as your best fitting pair.

aldo best fitting shoe

The tool then compares data from this brand to the pair that will fit you best. As well as telling you the right size, it will also indicate whether the overall fit might be snug, true to size, or loose.

Aldo’s is not the most exciting or interactive guide, but its premise (and the technology behind it) is still impressive, giving shoppers reassurance and lessening the chance that they’ll need to return a purchase.

aldo size recommendation

Nudie Jeans

Swedish denim brand Nudie Jeans is another retailer that uses shoppers’ existing clothes as a way of determining the best size and fit. Like the other examples, the interactive guide (which uses Virtusize technology) can be found on each product page.

nudie jeans size guide

It works by asking the user to choose a favourite garment (that fits well) as a reference, and then gives guidelines on how to measure key parts of it like the inseam, waist, and thigh length.

There is a fussier element to Nudie Jeans’ tool, perhaps meaning people might be less inclined to actually see it through. Shoppers will need to have a measuring tape handy, as well as be willing to go through the process of manually measuring their own clothes.

nudie jeans measurement

In comparison to Aldo, which does the hard work for you and collates its own data, it feels far less sophisticated.

Having said that, there is a reassurance that comes from measuring clothes yourself. Instead of trusting in invisible data (with no guarantee that it is correct), Virtusize at least ensures that the measurements you enter will be correct, perhaps resulting in a more accurate outcome.

nudie jeans recommendation

It might not be as slick as other size guides, but its higher attention to detail with measurements mean it could provide more long-term value.

Luna Sandals

Luna Sandals is a similar example to Nudie Jeans, in that it involves a manual measurement (that the shopper must make) rather than a digital one.

When you click on the size guide – which gives an overview of shoe sizes in comparison to measurements – it also gives you the option to ‘double check’ by printing off a shoe template. This allows you to compare your own foot to the actual size of the sandal, indicating how much room there should be behind the heel, in front of the toes, and so on.

luna sandals

This example might seem out-dated in comparison to other digital size guides, and sure enough, it’s not exactly the most innovative.

However, it does bring a little extra fun and quirkiness to the process, as well as giving shoppers the reassurance that they’re ordering exactly the right size.


Most size guides are solely designed to combat wrong-size purchases, but M&S’ bra size calculator aims to solve a wider problem. This is that a lot of women continue to wear the wrong bra size, largely due to reluctance in getting one properly fitted (rather than fault on behalf of the retailer).

bra size calculator

As a result, M&S has strived to replicate its in-store bra fitting service online, with a comprehensive and surprisingly detailed sizing tool.

Starting with the type of bra that best suits the individual’s needs, the tool asks users to measure themselves, as well as a wide range of questions relating to how their best fitting bra currently fits.

M&S bra size guide

Again, there could be some reluctance or drop-off when users realise they need to physically measure themselves, however this might be more expected when it comes to bras than other items of clothing. The greater need and desire for a well-fitting bra could also outweigh frustration over measuring.

Onto the process itself, and from how the cups fit to additional details on the size of shoulders and cleavage, it is impressively detailed. As well as helping shoppers find the right bra size, the tool also points out why a current size might be resulting in problems, ideally setting them up for success with all future bra purchases.

M&S bra measurement

Finally, with the tool being one of the lengthiest and detailed in this list (and including a prompt to shop the right size at the end), it is likely to result in conversions from those who complete it.M&S bra calculator

More on fashion ecommerce: