What a great article, for those that want to track their progress on a manual basis, this really works well. Especially if you like to keep any trace of your holdings away from any external systems. The down side is you need to change the data with every purchase or a sell. But the data is invaluable and once you have it you will never want to be without it!
In the last year there has been a wide range of new trackers on the market so that you can easily track your Break Even in real time as you trade.
Here is an article showing you how
https://www.coinmarketman.com/blog/cryptocurrency-break-even-calculator/