Comment by NikolaNovak

The difference between employee salary and effective hourly rate, and billable rate, is not usually particularly secret, and usually doesn't make any sense first time, or even 20th time one sees it. The billable rate is some outer space number with no meaningful connection to real world. If you stick long enough you'll realize that billable rate is not what consulting company charges for you. It's what they charge for you and the non billable boss, senior partner, salesperson, delivery excellence review people, Admin and hr support, half a dozen people who did the bids and proposal, legal, the first phase of the project company did as loss leader, and then for all those things multiplied by contracts not won. this too is not a particular secret either internally or to the client.

If you go as a independent contractor, you can bill close to that rate yourself, but may find that you can't bill quite that rate as the mandatory middle vendors will take their obligatory cut, you need health insurance and your own expenses and any moment you're not working whether between contracts or vacation is lost money. Still makes sense for some people, less for others. Depends on your expertise, preferences, sales and networking skills, and how good is your accountant. Always better to build reputation and then become small consulting company yourself, billing billable rates and paying salary rates to others.

(This is in the world of consulting. Math may be different in world of independent freelance technical developers)