A question about sorceress fire skill damage


Diabloii.Net Member
I've been working on putting together a meteorb sorceress for PVM / MF purposes. Since there won't be enough skill points to max ALL the fire skills, I'm trying to find out how meteor damage is calculated - so I can make the right decision about where to put those points that I do have available for fire skills - in fire bolt or fire mastery.

Currently if I take off all gear with + skills, I have 2 points in fire bolt, 20 points in fire ball, 20 points in meteor and 5 points in fire mastery.

This results in a meteor doing 2883 - 3075 damage - according to the game when I mouse over the meteor skill.

Now, a level 20 meteor does 955-1019 damage according to various sites, each point in fire bolt and fire ball increases meteor damage with 5 %, while a level 5 fire mastery skill increases fire skill damage with 58 %.

But how does the math work making all this add up to a 2883 - 3075 damage fire ball? That is what I'm trying to find out.

Alternative one (for the sake of simplicity I will be calculating only the minimum damages) would involve multiplying all the bonuses. This results in a fire ball with a minimum damage of

955 * 1.05^22 * 1.58 = 4414.

But this can't be right, the result is much more than 2883.

Another alternative would be adding rather than multiplying the bonuses, in a way similar to how I believe multiple enhanced damage modifiers are put together in this game. The formula:

955 * (1 + 0.05 * 22 + 0.58) = 2559

Closer, but still does not match the damage number reported by the game.

A third alternative is a hybrid of the first two alternatives

955 * (1.05^22 + 0.58) = 3348

- Still not right!

A fourth and final alternative - another hybrid:

955 * (1+ 0.05*22) * 1.58 = 3169

Not the number we are after.

So, how does this stuff work? What's the formula?

This is important if you want to optimize your skill point distribution in a build where all the four relevant fire skills can't be maxed. If the formula is most similar to the first alternative, and you have more than 46 skill points to invest in fire skills, you should put more points in fire bolt or fire ball rather than in fire mastery - contradicting what all the meteorb guides recommend.

An example: Say we have 70 pts to use in fire skills and want the maximum meteor damage.

10 - 20 - 20 - 20 points in bolt, ball, meteor and mastery would give a (using formula one)

955 * 1.05^30 * 2.63 = 10855 minimum damage fire ball.

A 20 - 20 - 20 -10 meteor however, would have a minimum damage of a whopping

955 * 1.05^40 * 1,93 = 12976.

While these numbers are obviously way off those presented within the game, the conclusion is that if the game calculates meteor damage similarly to forumla one above there is more to be gained by putting points into fire bolt or fire ball, than into fire mastery, after having invested only a few points into the fire mastery skill.

More exactly, taking fire mastery from level 2 to level 3 should increase meteor damage with a factor of 1.051, which is more than you would get from investing this point into fire bolt or fire ball. But increasing fire mastery from level 3 to level 4 increases meteor damage with only a factor of 1.049, which is LESS than what you would get from putting a point into fire bolt or fire ball. And this applies to all further increases in the fire mastery skill level.

The problem here is obviously that none of my four "formulas" give a damage output matching the one reported by the game. So how is this stuff calculated ???!??!;)


Diabloii.Net Member
Another option (which I think is correct) is that the level 20 Meteor fire damage listed (955-1019) is already including the synergy bonuses from the pre-req's Fire Bolt and Fire Ball.

So 955 Meteor min-damage should correspond to 955/1.1 = 868 RAW meteor min dmg

Now we add the synergy bonuses and fire mastery

868 * (1+ 0.05*22) * 1.58 = 2880

You said that the game lists 2883 as min Meteor dmg, which is close to my calculation since I did a round-off and the game also do some round offs and truncations.

Now, how to assign skill points in the Fire Skill tree for a MeteOrb sorc depends highly on how you play. If you will use FireBall more than Meteor it is best to max Fire ball, Fire bolt and Meteor and just put one hard point into Fire Mastery. If you are gonna use Meteor more than Fire Ball, max out Fire Mastery before the synergies


Diabloii.Net Member
Another option (which I think is correct) is that the level 20 Meteor fire damage listed (955-1019) is already including the synergy bonuses from the pre-req's Fire Bolt and Fire Ball.
This makes a lot of sense. Thank you!


Diabloii.Net Member
drmalawi's right about prerequisite synergy bonuses being included. Basin Wiki's Meteor page has level 1-60 stats excluding synergy bonuses: level 20 Meteor inflicts 869-927 fire damage, before +10% Fire Damage from a point each in Fire Bolt and Ball increases this to ~955.9-1019.7 (*1.1), which is truncated to 955-1019. However, the smallest unit of damage isn't a point but 1/256 point, and it's truncated at the end of each stage of the skill damage calculation.

So level 20 Meteor with 22 points in Fire Bolt and Ball (+110% FD) and level 5 Fire Mastery (+58% Fire Skill Damage) results in the following:

Min = 869 * 2.1 * 1.58 ~ 2883 (or 2883.3359375 (+86/256) exactly)
Max = 927 * 2.1 * 1.58 ~ 3075 (or 3075.78125 (+200/256) exactly)


Europe Trade Moderator
A fourth and final alternative - another hybrid:

955 * (1+ 0.05*22) * 1.58 = 3169
It's this one BTW. The mastery and synergies have multiplicators of their own and the percentages don't stack exponentially, they are just added up each.

As said, damage calculators probably include synergy bonuses from prereqs if you make skill investmants like on your character instead of just adding a +20 bonus to fuireball. You could check that e.g. by equipping a non-fireball user with two Trang Oul pieces and comparing the fireball damage with what the calculator comes up with.


Diabloii.Net Member
Thanks for the info, guys.

There are definitely a lot of not so obvious mechanics involved in this game. Makes tweaking a build interesting.