Most freelance rate advice says "take your old salary, divide by 2,080 hours, and double it." That rule is easy to remember, but it hides the three things that set your real rate: how many hours you can actually bill, self-employment tax, and the costs an employer used to pay for you. Here is how to work the rate out backwards from the money you want to take home. I also put the whole thing in a free freelance rate calculator that runs in your browser. 1. Count billable hours, n...