Be sure to research for a formula for your hourly rates. You probably want to take your salary or desired salary, calculate out the hourly rate, and then double it at least. You'll be covering your own insurance, travel, equipment, and taxes are harsher.
This isn't a scientific post and it's been a while since I've done this, so put your work in. But your hourly rate as a 1099/consultant should be way higher than just dividing your salary.