Who files Form 941
Every employer that pays wages subject to federal income tax withholding or to Social Security and Medicare taxes must file Form 941 each quarter. Exceptions exist for very small employers (Form 944, annual), seasonal employers who can mark the seasonal box, household employers (Schedule H), and agricultural employers (Form 943).
Quarterly due dates
Q1 (Jan-Mar) is due April 30; Q2 (Apr-Jun) July 31; Q3 (Jul-Sep) October 31; Q4 (Oct-Dec) January 31. If you make timely deposits in full payment of taxes when due, you have an extra 10 calendar days to file the return.
Deposit schedule
Deposits are made on either a monthly or semi-weekly schedule, determined by your "lookback period" liability. Lookback liability of $50,000 or less makes you a monthly depositor; over $50,000 makes you semi-weekly. A separate $100,000 next-day deposit rule applies any day your accumulated liability reaches that threshold. All deposits must be made through EFTPS.
Reconciliation with W-2s
The sum of wages, withholding, and Social Security and Medicare taxes reported on the four quarterly Forms 941 must equal the totals on the annual Forms W-2 and Form W-3 transmittal. Mismatches generate a CP-2100 or letter from the SSA and require explanation. Reconcile every quarter, not just at year-end.
Schedule B for semi-weekly depositors
Semi-weekly depositors must attach Schedule B (Form 941), which shows tax liability by date — not by deposit date. The IRS uses Schedule B to compute failure-to-deposit penalties on a per-day basis, so accuracy matters even when total liability and total deposits agree.
Penalties for late or missing filings
Late or missing filings of Form 941, Employer's Quarterly Federal Tax Return draw distinct penalties depending on the form: failure-to-file (5% per month, capped at 25%), failure-to-pay (0.5% per month), failure-to-deposit for payroll forms (graduated based on lateness), failure-to-file information returns (per-return penalty that scales with size and lateness), and accuracy-related penalties (20% of underpayment for negligence or substantial understatement). The dollar amounts are not trivial. Calendaring the form's deadline, setting up an electronic reminder a week in advance, and using a payroll or tax-prep service that auto-files are the cheapest defenses against accidental late filings.