Ryanair's app now measures luggage – but can it really help you obey its strict bag rules?

Budget airline Ryanair has launched a new 'bag sizer' tool on its iPhone/iPad app, which scans your hand luggage to check whether it fits within its strict measurements.

Under current Ryanair rules, unless you pay extra, you can only take one free 'small' bag into the cabin, measuring 40cm x 20cm x 25cm. If you pay at least £6 for priority boarding, you can bring your small bag plus another 'cabin' bag (not exceeding 10kg and dimensions 55cm x 40cm x 20cm).

Ryanair's new bag sizer tool uses your mobile's camera to scan your hand luggage and show you whether your bag fits either of these size specs. In theory, that's a big help for MoneySavers because it stops you a) underestimating the size of bag you can take in the cabin and shelling out unnecessarily for hold baggage and b) overestimating the size of bag you can take and being hit with a surprise £25 fee to check in your bag at the gate.

But, and this is very BIG 'but', Ryanair's new tool comes with an important disclaimer. The app, which the airline says is technically in 'beta' or testing mode at the moment, admits that "this technology is not 100% accurate" and clearly warns "it is your responsibility to size the bags at the airport."

So – is the new feature any help at all? Or will you still need your trusty tape measure to be sure? We put it to the test...

Master Ryanair's mega-strict rules for cheap flights by checking our 20 Ryanair Tips.

How does Ryanair's Bag Sizer tool work?

OK, I'm not a specialist technology reporter and quite frankly, I have no idea how a small camera on your phone allows you to measure a 3D real-life bag accurately without anything for context.

But I'm told it uses something called AR (Augmented Reality) technology. Basically, the idea is you point the camera on your phone or tablet at a bag, and move it around a bit.

The new tool is only available via the app on iPads and iPhones that have AR technology (so the iPhone 6S onwards and most iPads made since 2017 – sorry, Android users). Here's a step-by-step guide on how to use it:

  1. Open the Ryanair app, and click 'Does your bag fit?' in the middle of the page, followed by 'Let's scan'.

  2. Choose which type of bag you're trying to measure – a 'small' bag, which must fit under the seat, or a cabin bag. Or you can choose 'not sure', and it'll make an educated guess based on your bag size.

  3. Then point your camera at the bag and move the phone around the front, side, top and back, slowly, while holding down the scan button.

You will then be told the size of the bag and whether it fits.

How accurate is it?

Ryanair says on its app that the tool isn't 100% accurate, and it's right – but it's not bad.

We tested it on seven bags of varying sizes. Generally, with traditional airport wheelie bags, the bag sizer was more or less spot on, but with rucksacks and holdalls – the sort of bags that vary in size depending on how much you stuff into them – it was much less reliable.

For example, we measured one holdall as 54cm x 30cm x 28cm, but the app said it was 53cm x 33cm x 30cm. We assessed another as 42cm x 30cm x 19cm and the app said it was 49cm x 29cm x 29cm. And one black rucksack simply wouldn't seem to scan at all, despite repeated attempts.

To be fair though, some of the rucksacks and holdalls were hard for us to measure, and we ended up with different results depending on who was wielding the tape measure. So this isn't an exact science.

We found the following improved the accuracy of the tool:

  • Moving the phone slower when measuring the bag.
  • Measuring bags in a plain, white-walled room with no shine from floor or glass.
  • Keeping other items out of shot.

To be safe, you'll still need to use a tape measure...

While the app is fun to try out and a clever piece of tech, the big problem is the uncertainty. Even if the tool says your bag will meet Ryanair's strict criteria, the app itself warns that's no guarantee you won't end up facing an extra charge when you get to the airport.

So ultimately, to be safe, you'll have to measure the bag with a tape measure (and probably err on the side of caution), which raises the question of why you'd really want to use the tool in the first place.

I guess if you were stuck in a secluded (but well lit) log cabin with a smartphone but no ruler or tape measure in sight the evening before a cheap flight to Corfu, this app could come in quite handy.

What other similar tools are out there?

Price comparison site Kayak and budget airline Easyjet both have similar tools on their apps that allow you to check the size of your luggage. Kayak's works on iOS and Android, while Easyjet's only works on iOS.

When we tried it out, the Kayak app seemed to be fairly similar to Ryanair's, except it measures dimensions in inches rather than centimetres.

The Easyjet app doesn't actually measure your bag in the same way as the other two, but instead provides you with an image of a cage, like the ones you would see at an airport, and lets you see if your bag will fit within it.

Crucially though, neither app guarantees that if the tool measures your bag as being smaller than the maximum measurements, it'll be accepted at the airport. Kayak's app warns when giving you the results that airlines "might or might not" accept your bags, whereas Easyjet's says of your bag: "If it fits inside the maximum cabin bag dimensions you're good to go."

So we reckon you're probably going to need that tape measure with these apps too...