As far as i know total damage is calculated like this(For magical weapons). Str modifier + weapon damage + Magical power available x damage in paranthesis. Not factoring the elemental damages.

But it doesnt seem that way.

My character has 20 str (Damage bonus : 20)

Magick axe : 1-12(+10)
Magical power available %60

So final damage should be : 1-12 + 6(damage in paranthesis) + 20(STR bonus) = 27 - 38

What i see on sword icon on inventory Damage = 27-36

Well 2 less max damage isnt that much of a problem but, now lets use filament sword:

Filament sword: 5-10 ( + 12) Crit Hit effect = + 50 Crit Fail = + 20
Magical Power available = %56

I would round up Magic power available to %50

Final damage should be: 5 - 10 + 6(damage in paranthesis) + 20(STR Bonus) = 31 - 36

Damage on sword icon on inventory(down left corner red icon) : 24 -24

It just doesnt make sense in anyway. And i dont understand why higher damage weapon hits lower.

a. Magick axe: 1-12, you see the number 12? it has a limitation that is 3x from the total basic max, so 12 x 3 = 36, 36 can be the max of this weapon, even if you have more damage bonuses, with this weapon the max will always be 36

b. Filament sword: 1-8, same rule as above, 8 x 3 = 24

c. Welcome to the forum

Hello and thanks for the answer.

But filament sword is 5-10, shouldnt it be 10 x3 = 30 max damage?

In version 1.0.6.4 and 1.0.7.4 the description says: 5-10, but the total damage is capped at 24; in UAP (Unofficial Arcanum Patch) the description says: 1-8 and the total damage is capped at 24, so I am guessing it was a bug that was fixed by the UAP.

UAP fixes many more little bugs that the official Patch 1.0.7.4 didn't fix, so I highly recommend you to install it.

Yes the item description is probably wrong in your version.

I can confirm that item description (what shows in the center bottom box on main screen) can refer to a separate file independent from the item properties.