How do I estimate W-2 numbers using my last paystub?

While waiting for my W-2 to arrive, I would like to enter estimates into my tax program so that I can gauge my tax liability. (Of course, I won't file until I've received the actual W-2 and adjusted my estimates).

I found some basic info about estimating the W-2 numbers here:
http://vpf-web.harvard.edu/ofs/payroll/e...

It appears I just need to subtract pretax items from my gross income to get box 1 and 16 (federal and state taxable wages). But how do I calculate social security / medicare income? The web site above implies that it is somewhat different, but doesn't detail what the differences are.

The reason I'm trying to estimate all 4 numbers (federal income, state income, social sec income, medicare income) is because the tax program won't let me continue to the next screen without that info.

The socail secuirty and medicare tax will tell you how much the ss and medicare wages are. Take the ss tax and divide by 6.2% and divide the medicare wages by 1.45%. Assuming your paycheck is correct and they usually are in this regard then you will have the wages you need.

It is your gross pay and your federal tax that was taken out. Good luck!!

Just look at your gross amount (before any deductions) that will give you the first number you need.. you also need to figure out what is your deductions are.. yourself. yourself and spouse.. any other dependent children. Then look at the amount the Feds took out of your check.. just the income tax stuff.. not the Medicare, or any insurance etc. etc.
Mostly you work with those 2 numbers, its not hard to do your taxes just read the booklet when you get it and follow the directions. If its a normal tax return you don't need to pay anyone to do the tax forms, remember irs.gov is also a place to help without paying for it.

All the information should be on your pay stub - FICA is social security and medicare combined. If this is why you are having a problem - go to the IRS web site and do a search for circular C - within this you can find the % you need to use for both social security and medicare.

Other than that - all info should have you year to date info on the stub. Total deductions etc.

And you are right about the pre tax part -

From your paycheck, subtract 401K money.
This gets you to social security wages.
From here, subtract your pre-tax benefits.