There are finally new dimensions for Ryanairs carry on luggage. Better still is we are finally getting our heads around what to buy to maximise this to the limit.
There are 2 pieces free of charge per person.

Carry On One : 55cm x 40cm x 20cm MAX 10KG weight

Carry On Two : 35 x 20 x 20 no dimensions given nor weight limit. I assume its like the guidelines for the handbag. 

Check on Ryanairs Bagage Page to see if it has changed correct at date of publish.

Be careful of tiny kids backpacks as they are counted as luggage ! They don't hold much. We have seen in the videos that kids trunkies DO fit in the Ryanair test device as well. Watch both videos and don't get caught out.

Amazon have a very handy link to shop for lugagge by airline click here to test it out.

Here is a roundup from the independent as further reading for the discerning shopper !