WHY DOES IT SAY FREE GEMS!!!!

Very confused about why it says free gem calculated. You could of said C.O.C calculater. And in the description say "tells how many gems you will need to buy or how many you will need. The guide by the way is VERY OUTDATED!!

Compactanimalo about Free Gems Guide Calculator for Clash Of Clans - Coc & Xmod - No Hack