This is a package for Mudlet that adds a command for calculating lesson costs for Iron Realms Entertainment games. The basic syntax is LESSONCALC <skillrank> <percentage> TO <skillrank> <percentage>. It also supports using LESSONCALC <skillrank> <percentage> PLUS <number of lessons>. The second usage will calculate how far you'd be in the skill if you added that number of lessons.
I recommend using LessonCalc alongside the websites "THE WEEKY PEEDIA LIBRARY" (https://sites.google.com/site/xieltalnara/home) and "Archives of Lusternian Lore" (http://wiki.lusternia.com/Main_Page) as these sites list what skillrank and percentage each ability is learned at.
NOTE: This package was originally made for Lusternia but should work reasonably well with any other IRE game. Just note that the skillrank "skilled" is called "master" on Lusternia. The number of lessons between skillranks doesn't differ very much between the IRE games, but be aware of this inaccuracy.