Along with actually depositing your federal payroll taxes, you also have an obligation to file periodic returns that show how you computed your tax liabilities. The returns you must file for your income and FICA taxes are different from the returns you file for your FUTA taxes.
Income and FICA taxes: You must file Form 941, Employer's Quarterly Federal Tax Return, to report both the federal income taxes you withheld and the FICA taxes you withheld and paid during a calendar quarter. The deadline for filing the return is the last day of the first month after a quarter ends. However, if you've been timely with each of your deposits during the quarter, you're entitled to an automatic 10-day extension. No other extensions are permitted for filing Form 941.
FUTA taxes. For FUTA taxes, you must file an annual return on Form 940, Employer's Annual Federal Unemployment Tax Return. A shorter and simpler form (Form 940-EZ) is also available if you meet certain conditions: if (1) you paid all your unemployment taxes to a single state, (2) you paid all the taxes by their due dates, and (3) and all wages that were taxable for FUTA tax purposes were also taxable under the state's unemployment tax law.
The deadline for filing the return for each year is January 31 of the following year. However, if you've been timely with each of your FUTA tax deposits during the year, you're entitled to an automatic 10-day extension. The IRS may allow you a further extension of up to 90 days upon your written request.
Timely filing rules. If the due date for your Form 941 or Form 940
falls on a Saturday, Sunday, or legal holiday, you have until the next business
day to timely file the return. A mailed return that bears a postmark indicating
that it was mailed on or before the due date will be considered to have been
timely filed even if it is received after the due date. If you're planning to
rely on the "postmark" rule, send the return by registered or
certified mail and request a return receipt. Using one of these mailing methods
will give you written proof of the postmark date.