Another way to approach this is to find the salary for a similar position then either x1.5 or x2.0 it. When working for yourself you have to incorporate expense

Another way to approach this is to find the salary for a similar position then either x1.5 or x2.0 it. When working for yourself you have to incorporate expenses (rent, insurance, hardware, services, accountancy etc.). From there work backwards to an hourly rate. One metric is Salary/2000 = Hourly Rate. You can use this to create a daily or weekly rate. You may need to talk to an accountant. You may need to charge VAT and will almost certainly need to set up as at least a sole trader.