The penalty for failing to file on time is five percent per month of the balance owed. The penalty for paying late is 0.5 percent per month of the balance owed. This rate drops to 0.25 percent per month for a taxpayer who files on time and enters into an installment agreement with the IRS to pay the balance owed. There is no late filing penalty on a refund return, but a taxpayer who fails to claim a refund within three years of the filing deadline generally loses the right to that refund. Taxpayers mailing their returns should be sure to get them to their local post office before the last pickup of the day.
Some post offices stay open late to accept returns for a deadline day postmark.
Taxpayers may also use designated private delivery services to meet the filing deadline. The four companies involved Airborne Express, DHL Worldwide Express, Federal Express and United Parcel Service can provide details on which of their services qualify and how to get proof of timely filing. As of April 6, the IRS had already received nearly 5.2 million computer-filed returns from taxpayers doing their own returns, surpassing the 5 million total for all of last year. This segment of e-filers has shown the largest growth rate, up more than 35 percent over the same period last year.