Based on the data from what someone wrote about max trainer level in another forum, click this link to see the algorithm for max cp increases as you're leveling up. Here is the link to the datamining: 

https://gist.github.com/KazWolfe/68e10ebf1ed41ae1ae6de2350d5de884#file-pokemon-go-data-dump-txt-L618


Also-- there's a lot of other useful info in that data, so enjoy ;)

Source article:

"According to this article the maximum trainer Level is 40. They found the information with datamining, there is no official statement about this.

Two more sources (thx to Kaz Wolfe): source1 source2

You need 5 million experience points to reach from level 39 to 40.

Afaik at the moment (20.07) the highest level players reached is level 30 and they need 500k xp for level 31