The only way to begin to answer this is with a Good Faith Estimate. Your lender should have provided one by now.
If you're wondering if your lender's fees are reasonable, you'll need a GFE from another lender or two.
The closing costs are going to vary by the factors listed in the previous answers, and also by loan type and interest rate. By that I mean that there may be different fees for an FHA loan vs. Convetional vs. VA vs. other (and there are plenty of "other" out there).