Form 941 is the Employers Quarterly Federal Tax Return, which businesses use to report income taxes, Social Security tax, or Medicare tax withheld from employees paychecks, and to pay the employers portion of Social Security and Medicare taxes. The form needs to be filed regularly, four times per year, with deadlines on April 30, July 31, October 31, and January 31 of each year. The form also provides space to calculate and report Social Security and Medicare taxes, and quarterly adjustments to Social Security or Medicare taxes for things like sick pay or tips.

Businesses need to fill out Form 941 to report federal withholdings from employees, including information such as wages, employee tips (as reported), federal income tax withholdings, employer and employee shares of Social Security and Medicare taxes, and additional Medicare tax withholdings. Employers who withhold taxes from employee payroll checks are required to fill out a 941 four times a year, even if they have no taxes to report. The main exceptions are people who have household employees like housekeepers or maids (filed with a 1040 tax return) and agricultural employers (use Form 943 instead of 941) .

There are two options for filing Form 941: by mail or electronically. The most convenient option is to use the federal e-File system, which can be accessed through many common small business tax software providers, such as TurboTax, H&R Block, or TaxSlayer. If a business chooses to file by mail, the mailing address depends on the state the business is in, whether they are submitting payment with their return, and what quarter they are filing for. Sending 941 forms by mail must be postmarked by the U.S. Postal Service on or before the due date.