how is hitting calculated?

[HunkyDory]

Can anyone give me the maths for calculating hitting in combat? or maybe redirect me to a site that has this information?  ;)

I quote from this thread on the Amazon Basin :

Let us do a little math (for an Amazon) :

I assume that the actual formula was not changed in 1.10.
If Hell Cows in 1.10beta have around 1500 defense that assumption is right.

First we need to calculate our Attack Rating as follows :
(((Dexterity * 5) -7 - 23) + Sum of +X to AR items) * (1 + ((Sum of +% to AR items + percentage of Penetrate Skill) / 100)) (1)

Let us assume a level 70 Amazon with 300 Dexterity and no bonusses.

(300 * 5) - 7 - 23 = 1470 Attack Rating.

Now we need a suitable Monster like a Hell Cow which has level 81 and a Defense of 1500.

We can calculate the Chance to Hit a Hell Cow as follows :
200 * (AR / (AR + DR)) * (AL / (AL + DL))
AR is Attacker's Attack Rating
AL is Attacker's Level
DR is Defender's Defense Rating
DL is Defender's Level

Dexterity = 300
AL = 70
DR = 1500
DL =81
Attack Rating is ((300 * 5) - 30 = 1470
200 * (1470 / (1470 + 1500)) * (70 / (70 + 81))
1470 / (1470 + 1500) = 1470 / 2970 = 0.49
70 / (70 + 81) = 70 / 151 = 0.46
200 * 0.49 * 0.46 = 45% Chance to Hit

If we change nothing else but the Attacker's Level we get the following table :
Level 70 is 45% Chance to Hit
Level 75 is 47% Chance to hit
Level 80 is 48% Chance to Hit
Level 85 is 49% Chance to Hit
Level 90 is 50% Chance to Hit

If we use an Eth rune in the bow we will lower the Defense Rating that the Hell Cow has to :
1500 - (1500 * (25 / 100)) = 1125 Defense Rating

Once again an example at level 70
Dexterity = 300
AL = 70
DR = 1125
DL =81
Attack Rating is ((300 * 5) - 30 = 1470
200 * (1470 / (1470 + 1125)) * (70 / (70 + 81))
1470 / (1470 +1125) = 1470 / 2970 = 0.56
70 / (70 + 81) = 70 / 151 = 0.46
200 * 0.56 * 0.46 = 51% Chance to Hit

If we change nothing else but the Attacker's Level we get the following table :
Level 70 is 51% Chance to Hit
Level 75 is 53% Chance to hit
Level 80 is 54%Chance to Hit
Level 85 is 57 Chance to Hit
Level 90 is 58 Chance to Hit

I can't get the math to match the character screen 100% but it is very close.

I hope this helps you.

Regards, Hunky

(1) All math is unconfirmed, just an assumption I make as to how it works in 1.10
edit: and Hammerman confirmed on the LL that it looks that the To Hit formula is not changed in 1.10
and Hell Cows have 1000ish defense. So that changes the math a tad.
I am going to check if my Chance To Hit corresponds to all this in a game.