- There is no penalty if you're getting a tax refund, provided you file within 3 years of the April 18, 2016 deadline (or October 17, 2016 deadline if you filed an extension).
- After 3 years, unclaimed tax refunds are forfeited and become the property of the U.S. Treasury.
- There is no penalty if you filed an extension and paid any additional taxes owed by April 18, 2016, as long as you file your return by the October 17, 2016 deadline.
- A late filing penalty applies if you owe taxes and didn't file your return or extension by April 18, 2016.
- This penalty also applies if you owe taxes, filed an extension, but didn't file your return by October 17, 2016.
- The late filing penalty is 5% of the additional taxes owed amount for every month your return is late, up to a maximum of 25%.
- If you file more than 60 days after the due date, the minimum penalty is $135 or 100% of your unpaid tax, whichever is smaller.
- Tip: The late filing penalty can be 10 times higher than the late payment penalty. If you can't pay your tax bill and didn't file an extension, at least file your return as soon as possible! You can always amend it later.
- A late payment penalty applies if you didn't pay additional taxes owed by April 18, 2016, whether you filed an extension or not.
- The late payment penalty is 0.5% (1/2 of 1 percent) of the additional tax owed amount for every month (or fraction thereof) the owed tax remains unpaid, up to a maximum of 25%.
- For any month(s) in which both the late-payment and late-filing penalties apply, the 0.5% late-payment penalty is waived.
Best-case scenario: You file your return on April 29 (2 weeks late) and submit your payment for $1,000. You would likely owe an additional $50 for the late-filing penalty ($1,000 x .05 = $50).
(Had you filed an extension by April 18, 2016, your late-payment penalty would be only $5 instead of $50. It definitely pays to file an extension!)
Worst-case scenario: You finally file your 2015 return in April of 2021, 5 years late, and submit your payment for $1,000. You would likely owe an additional $250 for filing late ($1,000 x the maximum .25), plus possible interest.