Magic find math

[Deleted]

I've got a bit of math to check with you guys. Just for fun :P
First of all I've got calculations based on info here http://diablo.wikia.com/wiki/Magic_Find (not sure if reliable in any way).
Second, I hope this is still true - when item drops it checks if this is magic item, if so - checks if rare, if so - checks if legendary.

Max magic drop % = 100 @300% MF
Max rare drop % = 30 @300% MF
Max legendary drop % = 10 @300% MF

MF boost = 10 * additional party member
Torment boost = 1.15 * torment level
Rift boost = 2

Let's count for T6 rift, party of 4, best topaz gem (41%MF):

MF = (41 [gem] + 30 [party]) * 2 [rift] * 6 [Torment lvl] * 1.15 [Torment boost]) = 71 * 2 * 6 * 1.15 = 979.8
Chance for magic item = 979.8%
If magic test passed: chance for rare item = 97.98%
If rare test passed: chance for legendary item = 32.66%
So chance for legendary drop is 9.798 * 0.9798 * 0.3266 =~ 3,1354

While solo T1 rift, no gem:

MF = 10 [minimum] * 2 [rift] * 1 [Torment lvl] * 1.15 [Torment boost]) = 23
Chance for magic item = 23%
If magic test passed: chance for rare item = 2.3%
If rare test passed: chance for legendary item =~ 0.77%
So chance for legendary drop is 0.23 * 0.023 * 0.0077 =~ 0,000041

This seems to be way to low. And there is no change between solo play and party of 2.
I don't know where did this website get the numbers for Torment and Rifts but do you think this is accurate?

[Wengel]

somehow i find it unlikely that the chance of finding a legendary in a T1 rift alone is 24390 to 1... Without going into any details about the math and the fact that there cannot be more than a 100% chance to find a magic item (to my logic at least).

[Danalar]

1.15*[Torment Level] does not make any sense, it's most likely 1.15^[Torment Level] or 1+(0.15*[Torment Level]).
In the first case, the initial result would be 328.45, in the second it would be 269.8.

[Deleted]

Math in details in case this is 1.15 ^ Tlvl (power)

T6 rift, party of 4, best topaz gem (41%MF):

MF = (41 [gem] + 30 [party]) * 2 [rift] * 1.15 [Torment boost] ^ 6 [Torment lvl]= 71 * 2 * 2.313 = 328.446
Chance for magic item = 328.446%
If magic test passed: chance for rare item = 32.8446%
If rare test passed: chance for legendary item = 10.9482%
So chance for legendary drop is 3.28446 * 0.328446 * 0.109482 =~ 0.118

While solo T1 rift, no gem:

MF = 10 [minimum] * 2 [rift] * 1.15 [Torment boost] ^ 1 = 23
Chance for magic item = 23%
If magic test passed: chance for rare item = 2.3%
If rare test passed: chance for legendary item =~ 0.77%
So chance for legendary drop is 0.23 * 0.023 * 0.0077 =~ 0.000041

Chance above 100% means that this is guaranteed drop but number is used for further calculations where it is reduced.

Anyway, this chance seems to be too low.

[theburned]

First of all as mentioned it's 1.15^torment level.
the 1+(0.15*torment level) is wrong.
also the magic find has 100% effectiveness for magic items 30% for rares and 10% for legendaries.
So if you have 300% magic find you have 30% extra chance to find legendaries.
so it's 7.1% if you have topaz + 3 in party. (41%+30%)*10%

also the rift bonus is exclusive to legendaries and just means rifts drop 100% more often than outside of rifts.
and I am not sure, but I don't think they are using the roll for magic then roll for yellow then roll for legendary item anymore if they ever did.

http://www.diablofans.com/forums/dia...alysis-rifting
well this explains better than I can ever hope to, though it is outdated and the 1.25 rift bonus is now 2x instead.

TL;DR the current chance to find a legendary * (1 + 1/10 MF) = new legendary drop chance.

[Deleted]

Thanks, theburned! This makes more sense and feels more appropriate.