how to include criticals in dpm dps?

Help pls. I am working on a dmg range and dpm calculator and I need to figure out crit rates work in to those formulas.

total damage * critical chance * 1.5?

I suck at that kind of stuff, though, so don't take my word for it. XD

Scalar damage multiplier due to criticals: 1 + crit rate x average damage increase due to critical hit. Default unmodified damage multiplier for criticals is anywhere between 1.2x to 1.5x, is modified by buffs/skills.

E.g, Battle Mage criticals deal 1.4x to 1.5x damage unbuffed due to Battle Mastery, average 1.45x. They have a 45% crit rate, therefore on average their overall damage is increased by (1 + 0.45 x 0.45)x = 1.2025x due to criticals.

Wondering though, there's a decent DPS calculator right here on SP that you can modify to your own ends, why not use that?