Calendar Reminders Due Date Federal Tax Deposits Due 15th of every month unless required to file more frequently due to Gross wage amounts Sales, Meals & Room 20th of every month Mass Withholding 15th of every month Corporate Tax (calendar year filers) 15th of March Corporate Tax Extension (calendar year filers) 15th of September Non-profit (calendar year filers) 15th of May Individual Returns 15th of April Extension - Individual (6-month) 15th of October   Our office is located in Vineyard Haven, Massachusetts within the Woodland Center.