Results of this calculator heavily depend on your inputs — more accurate values will yield in more accurate estimation. Also, there are certain
bonuses (
backfill,
doubled XP on a last week of a season and
event challenges) that this calculator does not take into account, but this shouldn't be an issue (feel free to double your playtime value if it is a last week of a season or complete event challenges and enter your new XP level if there is an event going on).