I found a set of calculators here that seem to take into account at factors like employment tax, retirement, and insurance. And it’s pretty fast, containing just on interview page that constantly updates.

Salaries for all sorts of professions are well published, e.g. salary.com and others.

The question is, how much above the hourly wage of a salaried employee should a contractor charge to end up at the SAME real compensation. This needs to take into account benefits (401k, other pension, health care, paid vacations, etc.), taxes (like self-employment tax, business licenses, etc.), contractor owned, rented or hired resources (equipment, office space, office help).

If I can show such an equation, based on real hard costs and real salary market data, then I can justify my rates, but if I say I need $X to pay my mortgage, then all I may hear is get a smaller house…

So the calculator is great, but it covers only half the equation, the one that answers the contractor’s needs, it doesn’t answer the client’s questions as to why he should pay that much.

Michael from designandprogram.com