NOTICE: As of November 30, 2016 (GMS v178 - Limitless), the visual damage range cap has been raised to 99,999,999. The primary motivation behind the creation of this tool was to enable accurate computation of damage ranges beyond 2m~2m. Thus, this damage calculator is essentially obsolete, except in the following situations: (1) players are able to surpass 99,999,999 damage range, and (2) for players who wish to calculate damage ranges based on hypothetical upgrades or downgrades in equipment, skills, and/or stats. In addition, final damage is now included in the damage range calculation; if your class has a skill that gives final damage, you should fill in your % FINAL DMG in the designated box.
A common misconception in MapleStory is that the maximum damage range is 2m~2m. While this is the maximum displayed damage range, there is no bound on the actual damage range. The creation of this tool was motivated by this fact, and is intended to allow funded players to monitor the effects of their upgrades after 2m~2m range. As such, this calculator is optimized for high-level players. In particular, it is assumed that the character has maxed out all mastery and relevant passive skills all the way through 4th job.
It is recommended that you watch the tutorial video before using the calculator.