You must file your IRS extension request no later than July 15. Doing so will give you until October 15 to file a federal return.This gives you until October 15 to file without penalties. We will automatically grant you an extension of time to file up to 60 days from the April due date or the original due date of the NPT return. The Pennsylvania Department of Revenue will grant up to a six-month extension of time for filing a Pennsylvania income tax return upon request. Plication for Extension of Time to File Local Tax Return form from the list. An NPT return must be filed irrespective of whether not the business has an office or business location in the city. "The best way to avoid the hassle of waiting is to fill out your city tax return today and mail the return.