Hey OP, I just used the PP's recommendation on the ADP calculator. I used my 2012 salary and it was within $200 of what I usually received on my paycheck. I'll assume the $200 difference was due to healthcare, since I paid around $800/month for that. So it's pretty darn accurate!

I agree on ADP. Start by putting in your current salary and info though, try to get it to match up.

Also remember there's a cap on SS contributions at something like $110k - so if your salary bump puts you over that, or if you are already over that, keep in mind ADP will assume your starting YTD income is $0. Thus, the increase is "under reported"

Here is ADP's Salary calculator. I use it all the time.

http://www.adp.com/tools-and-resources/calculators-and-tools/payroll-calculators/salary-paycheck-calculator.aspx

A rough calculation would be to just look at the percentage increase of your raise (e.g. 3%) and increase your current take-home pay by that amount. It's not exact but it's reasonably accurate. If you want to get more detailed, you would have to look at your federal and state withholding tables, etc. to determine how much you are having taken out each pay period for taxes, social security, medicare,401K, health insurance, etc.

I am expecting a raise soon and trying to figure out what my new take-home pay will be. Anyone know a good online calculator?