For taxpayers who believe they are owed a refund from the Internal Revenue Service, you have three years from the original due date of the return in order to file and claim your refund. However, if you wait too long you will forfeit any refund you might be entitled.
If you are filed your tax return after the October 15th deadline, and do not owe any tax when there are no late filing penalties or interest.
For more information, visit: https://www.irs.gov/individuals/dont-lose-your-refund-by-not-filing