You can still file. All hope is not lost. In fact, if you’re due a refund, there is no penalty for filing late (but keep in mind that there’s a 3-year window before you forfeit your refund, so be sure to file your 2012 tax return before April 15, 2016).
If you owe taxes, you’ll be subject to a late filing penalty: 5 percent of your unpaid balance per month, or part of a month, up to a maximum of 25 percent. Also, whether you filed an extension or not, a late payment penalty of one-half of one percent (0.5%) will also accrue each month or part of a month until the balance is paid in full. The IRS also charges interest on unpaid tax from the due date of the return until the date of payment, even if you were granted an extension of time to file the return.
Conclusion: if you owe, the sooner you file, the smaller your penalty. If you’re due a refund — well, what are you waiting for? Get ‘em done already and get that refund in your hands!