I've decided to use a CPA this year to file my taxes. I used turbotax to go through the motions, but for a little more money I'd rather have a pro deal with this. Understandably he's over capacity so I'll be filing an extension and he'll get to me in early May.

For lines 4 and 5 on form 4868, what number is used? Federal taxes, social security?

Here's the form: https://www.irs.gov/pub/irs-pdf/f4868.pdf

  • 1
    Depending on your state, check if you also need a state extension. In the (few) states I have personal experience, you don't have to file a state form if you file Federal 4868, but you still must make any needed payment, seperate and direct to the state. Commented Apr 7, 2016 at 3:29
  • It looks like CA doesn't require the filing of an extension if I don't owe additional money.
    – quid
    Commented Apr 7, 2016 at 17:06

1 Answer 1


If you've already used TurboTax on your 2015 taxes, you can use the numbers TurboTax gave you as your reasonable estimate.

Line 4 is your estimate of total tax liability for 2015. This would be line 63 of form 1040. This is Federal income tax only, not Social Security tax.

Line 5 is the total of tax payments you made last year. You should be able to read this off your W-2 forms, Box 2. It corresponds to line 74 on the 1040.

Line 6 is the difference between lines 4 and 5. You can't claim a refund on the extension, so if line 5 is more than line 4, enter 0. Otherwise, subtract line 5 from line 4, and enter it in line 6. This is the amount you should send in with the form to minimize any penalty due with your taxes later.

The TurboTax software can generate this extension form automatically, I believe.

Also, don't forget to give a copy of this extension form to your tax preparer. He will need to know the amount you sent in.

  • Line 63 does include Social Security and Medicare tax for self-employed, and some other (relatively rare) non-income taxes on 57-62. Conversely line 74 includes estimated payments and some credits as well as withholding -- and some (relatively rare) withholding is on 1099 series not W-2. Commented Apr 7, 2016 at 3:26

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .