This app is highlighting the size differences in high street shops

Want to navigate the high street without getting stuck in the changing rooms? US TOO.

One of the hardest things about online shopping (or just shopping in general), is the realisation that while you might be a medium in one shop, you might be a large in another - and a small somewhere else entirely. Meaning that you either end up forking out for three versions of every item - just to try them all on in front of the mirror and then attempt to make it to the post office in time to post two of them back - or you end up closing your eyes and crossing your fingers and hoping for the best. (And then attempting to make it to the post office in time to post it back anyway.)

Which is why we're completely obsessed with online shopping app Mallzee - and its new size differentation filter.

'Mallzee was invented to solve the problem of being able to find, compare and buy items from multiple retailers in one convenient place,' says Cally Russell, who created the app. 'As we worked to solve this more and more users told us they struggled to find products in the correct size. We needed to be able to give our users the ability to find, compare and buy items knowing that no matter which retailer they are from, they will be in their size.'

If you haven't used Mallzee already, it's basically like Tinder for shopping. Simply enter your criteria (e.g. 'midi dress'), and you'll see every item that matches your search, from pretty much every online shop out there, one at a time. Then it's just a matter of swiping right if you like the item, (in which case, it'll go into your favourites), or swiping left if you don't. In which case you'll never see it again.

The whole process is obscenely addictive and incredibly fun - not least because if you save your bank details, you can click 'buy' on any item and get it there and then (without having to rummage around in your bag for your purse, before painstakingly typing out your delivery address for every individual shop you're buying from).

But the really groundbreaking thing is its recognition that a size small in Zara is not the same as a size small in Miss Selfridge. Or Mango. Or River Island.

All you have to do is fill out your size profile, and from then on, you'll only see items available in sizes relevant to you. You don't even have to calculate whether you're a small in Topshop or a medium in Warehouse, because the app will do that for you.

And since shops seem to be unable to unify their sizing themselves (which would be the dream), this is definitely the next best thing.