Sometimes it’s difficult to tell what you are really worth. The job market is a fickle mistress and trying to benchmark your salary is often like trying to hit a moving object with a paper airplane. This is why a company like PayScale (found via our friends at Lifehacker) is so interesting.

PayScale allows employees to volunteer information about their employer, location and salary and in return they get what others in their area are being paid for the same job. This is great for anyone who is trying to figure out how hard to press potential employers and good for companies who want to see how they stack up compared to their competitors.

The system takes into account a wide range of data-points, including vacation time, health benefits, and profit sharing. Much of this information can only be found in their “premium” reports, but you can still compare salaries without having to pay a dime.

Before you head out to your next interview, I suggest giving PayScale a good look.