Carry-on size 55x40x20 cm-with Ryanair

RyanAir's website shows several apparently approved bags at 55x40x20 cm (21.6"x15.75"x7.87"), not 50 cm or 19.6".

Ryanair is 55 x 40 x 20 not 50.

Do you want wheels or no wheels?

The Ryanair's requirements are still half an inch shorter than most "standard" American carry on sizes. This was an issue I was having when deciding between air and train travel. The super cheap flight prices become super expensive as soon as you have to check a piece of luggage. How strict are they over have half an inch?

"How strict are they over have half an inch?"

Very. Those checked bag charges (and other charges) are how they are able to offer the cheap 'base' price.

But if you build in the cost of a checked bag when you book the flight, it's not really that much ... They get you for at-the-airport charges to check a bag that's just a little too big or too heavy. We just flew Budapest->Berlin, 2 people with 2 checked bags for about $75.

How strict are they over have half an inch?

Ryanair uses sizing checkers frames/boxes as do other carriers. They do not measure your bag. If it fits, it flies.

This is where non-rigid luggage works better than rigid luggage or luggage with rigid frames. If you can push your bag into the frame, it flies. The test is a fair one in that if you can push your luggage into the overhead, hopefully not mashing your fellow passengers stuff, you are legal.

I would not be concerned about the size. The weight is what will get you. 10 kilos (22 lbs) is very light for nearly all travelers coming from overseas, plus, you are only allowed one other small hand baggage...of which your day bag does not comply. Unless you will be using a Base, where you can leave the bulk of your stuff while you are using Ryanair, just pay for the checked bag, believe me, it will pay in the end and the total ticket cost will still be a bargain.

We flew Ryanair last fall Venice to Budapest, because we had to! We travel with 2 Rick Steves' convertibles, usually around 17-18 pounds. We had to get a Passport check at their check-in even with our having done on-line check-in. We walked not the counter with the bags on our backs, no one said a word. And we've never been questioned anywhere with these. If they want to put them in the sizer, go for it, these are soft and thus should always fit. If you have these. There should be no issue. 10kg is 22 pounds, if you are close, you can always offload a few pounds to a small daypack (which in our case, is rolled up in a main bag), which you are also allowed.

I am glad you posted this question. I will be flying Ryan Air from Dublin to Stansted in May and have booked with hand luggage only. My case is an Eagle Creek Tarmac International Carry on. 51 x 36 x 20 cm that does not include the wheels. With wheels my length is 54 x 36 x 20 cm. I am a little nervous that this will meet bag restriction requirements.

My mistake in the question
Ryanair is 55x40x20 cm
Which converts to 21.6x 15.7x7.87 in

Rick Steves rolling Carry on is:
21 X 13.5 X 9
So- it is still not meeting requirements on the width. Yes, they are very strict usually - I've flown them before. You have to put bag in the metal frame to see if it fits.

With the five of us we usually have each a carry on and then another bag or two to check.

The newer model of the Eagle Creek Tarmac International Carry On is 55 cm x 35cm x 20 cm and that includes handles and wheels.