Talk:Stacking/@comment-4091261-20150221202346/@comment-43526955-20190819035350

Or, if the stacking percentages are the same, it can be expressed as

1(1-x^n)

Take frozen heart or cold steel from randuin's.. they stack, and are both 15%

1(1-.85^2) = .7225 or 72.25%

That explains the multiplicative stacking of 27.75% attack speed slow.

It's the same with Illaoi's tentacle heals, which heal 5% of her missing HP.

x = missing hp

n= number of tentacles that slam at the same time and hit an enemy champion

x(1-.95^n)