The purpose of this application is to keep track of the hidden stats of your pokemon in a more friendly way than a spreadsheet or text file. I will not take the time to explain IVs and EVs here, as they are relatively complex mechanics. There is a wealth of information on how they are calculated and what they do, but the short version is that they are stats every pokemon has that are hidden and affect the visible stats.
The Pokesorter calculates the actual stats from the values you provide it, and can save files that are loaded later.
NOTE: This was something I made in my free time during my first CS class in high school. I've not since maintained or even looked through the code at length to see if it's acceptable.