Essentially as a contractor you should be making at least 2.5x what an employee would make. So if an employee is being paid $120,000 as is in a similar position as you you should be getting paid $300,000/year so you can make the same salary + a little more for the added costs of being a contractor.
What are these extra costs you might be wondering they are: Business registration, licensing, certification, life insurance, private medical/health/dental insurance, taxes, vacation, technology, bills, travel, parking, emergency funds, liability, general and umbrella insurance, car maintenance, car fuel, carl detailing and regular cleaning, house maintenance (yard, inspections, upgrades, insurance, etc.) or rent, payroll if you get your own subcontractors, overtime pay (if you end up working 60 hours a week you need to add in the costs of this. If your employer wants you to work more than that you can renegotiate your rates to accommodate), etc.
As an employee there is about 50% or more costs that you do not see as an employee. It is known and expected that contractors will be paid way more than employees as contractors take on 100% of the risks.