This is an updated version of @GottFaust's old calculator with updated game mechanics and powerful new features.
Requires java 1.7 or higher.
Calculates DPS with status effects.
Runs an exhaustively accurate simulation of your build versus selected targets.
Min/maxes your builds for you using the "Maximizer" function.
Fully supports rifles, shotguns, and secondaries.
Partial support for melee weapons and arcguns (Don't put too much faith in