Confused by the size of this 40L backpack

[OlsenZ]

Hi guys, I will go to the foot of Alps in July and choosing a 30-40L backpack now, I am with little experience and this is my first one.
There is one which seems pretty good to me, the capacity says 40L and size is 47x30x18, the size is confusing since I am also looking at a 30L one from Decathlon whose size is bigger: 63x30x23

Does it happen that small size backpack has bigger capacity? If so will small size gives me discomfort? I checked quite some other backpacks and found the Decathlon one has more “normal” size.

I put the link for both of them here:

https://www.mountainwarehouse.com/au/hi ... 3845.aspx/

https://www.decathlon.com.au/p/mountain ... 86738.html

Thanks in advanced !!

[fff]

I'm not a fan of either company-but to me the Decathlon one, even though it's very heavy for what it is, looks better and has the best set-up of pockets and is probably truest to size.

[Neo]

Hi I noticed on the Decathlon page, click the tab technical then has a spot where they say volume is measured by stuffing plastic balls in every pocket space then measure the volume of the balls.

Sometimes a website lists a package/delivery size instead of the actual items size.

Of the two I would lean towards the design of the Decathlon one.

[OlsenZ]

Thanks mate, I would consider the Decarthlon one too only thing to concern is as you said the weight, will do more researching.