Allow me to explain.
So, the overall size is 55x40x20 cm and the backpack, overall, is spacious and has a lot of pockets where you can fit gadgets, cosmetics etc.
The inside is long and wide enough and I could easily fit a pair of snickers too as well a spring-autum jacket. You definitely have room for a laptop too should you wish to work on your holiday (no!).
The pockets are very smart integrated – all your cosmetics will fit in there and you have room for the mobile chargers too. Oh, I added the underwear and socks in those smart pockets as well.