There are a lot of ways to track your profits. I mainly use altpocket for my altcoin investments (I can directly import my buy-sell logs from bittrex, this makes my life a lot easier when it comes to tracking my investments). And on my mobile device I use blockfolio to track my bitcoin investments.
If you don't have a mobile device or don't want to rely on a 3rd party service you can also do it the old-fashioned way and use excel. But that requires more time and some excel skills.