I agree, the items as well should display a volume and mass. A uniform or sleeping bag may not weigh much but it will take up half the space in your pack, a few hundred rounds of ammo may not take up much space, but it will weigh you down.

Just as a temporary bit of info, below are the capacites, in units of 6.5mm stanag and 9mm 16Rnd Magazines, of some clothing and pack items:

Clothes:
Combat Fatigues - 2 6.5mm STANAG and 1 9mm 16Rnd Mag
Combat Fatigues (Tee) - 2 and 1
Recon Fatigues - 2 and 1
Heli Pilot Coveralls - 7

Chest harnesses and LBVs:
Rangemaster Belt - 1
Slash Bandolier - 8
Fighter Chest Rig - 10
Chest Rig - 11
Tactical Vest - 12 and 1
Carrier Lite - 14
Carrier Rig - 20
Carrier GL Rig - 21
LBV Harness - 25 and 1
LBV Grenadier Harness - 28

Bags:
Bag - 34
Assault Pack - 34
Field Pack - 35 and 1
Kit Bag - 42 and 1
Bergen - 54
Carryall Backpack - 60

Hopefully this data helps a little until a comparison feature gets implemented.

This issue was processed by our team and will be looked into. We thank you for your feedback.

I had the same need for this information as you and found a way to gather them.

Look up my BIS forums thread :)

http://forums.bistudio.com/showthread.php?174855-Space-of-ruck-vest-uniform&p=2648242#post2648242

The size of object an object appears in orange when we try to put it in the bag or anywhere, this is good and enough (according to me)

But the capacity of backpack, crate, and any kind of boxes doesn't appear.
It will be very help full to see the capacity of any "containers" just to know which is the bigger...

Thanks for your work.

Virtual Arsenal kinda solved this I guess?