How does arena rating work?

[Alter]

How are these those rating numbers calculated? And how the heck do bots get gold ranking? They fight real people.

[Shiune]

It mostly works like that:

 

Usually there is a gap between 100 rating - means if you are on 1600 you can fight someone which is 1500-1700.

 

However it can happen that you fight against a player which is over 100 rating above you if you have a good win streak like 8 in a row vs.  someone which have lost a couple of matches in a row (so for example you are 1600 with 8 wins in a row and you play vs someone which is on 1720 which lost some games in a row) - at least that is what I have been told. 

 

Destroyer bots reach gold because there are many bad players which loose to them and because bots also meet other bots and there have to be a winner between them... though on EU there aren't any destroyer bots around anymore so I can't tell how it looks like on NA.