Hearthpwn

How many can I expect to pack (roughly) if I open 100 packs?

About 5 if you're not unlucky. The rate is 1 legendary per 20 packs and 1 epic per 5 packs.

2 minimum, almost guaranteed 3, 4 or 5 average, more if you’re really lucky.

Also, keep in mind that there is a pity timer which activates after you open 40 packs in a set, so if all 100 of your packs are from the same set, you are guaranteed at least two legendaries and ten epics, and you'll get a third legendary within the next 20 packs of that set.

2 if you've already opened 10 packs from that expansion. 3 if you have not.

Open more than 20 RoS packs, didn't see any leg. 

Quote from Hackneyed >>

Open more than 20 RoS packs, didn't see any leg. 

 He worded it poorly.

On average you'll get one legendary per 20 packs. At worst you'll get 1 legendary per 40 packs. 

As Tamika_Olivia said you will at minimum get 2 legendaries, 3 if you haven't bought that set of packs before. Because you'll get a guaranteed one within your first 10 packs.

Average is 1 in 20, apparently.

Guaranteed is 1 in 40.

So, if you have good luck, you'll get 5+. If you have terrible luck you'll get 2.

From my own experience, you should expect no less than 3.

I'm going to roll high and say 5 is minimum. Definitely NOT minimum possible because 2 is. But on an average day, I think this is what the RNG shall grant you.

Pretty much what others said, pity timer is 40 packs, so you are guaranteed to get at least 2 legendaries in 100 packs (from the same set, pity timers are set sensitive).

Three, if it is your first time opening ROS packs, since there is an extra pity timer of 10 packs for any new set that you didnt open packs from yet.

Otherwise the average rate is 1 from 20 packs, but it is called average for a reason.

Ok thanks all. Good to know :)

Currently saving my gold for the next expansion