The Small Business Tax Calendar: Deadlines by Month for Owners, Payroll, and Entities

Missing a deadline is one of the most avoidable tax problems. A calendar will not prepare your returns, but it can prevent the penalties and interest that come from forgetting them. This calendar covers common federal dates for calendar-year taxpayers. When a date falls on a weekend or federal holiday, the deadline generally moves to the next business day. Dates can change due to legislation or disaster relief, and state deadlines often differ, so verify each year.

January

• January 15: fourth-quarter individual estimated tax payment for the prior year (Form 1040-ES).
• January 31: Forms W-2 and W-3 due to employees and the Social Security Administration. Forms 1099-NEC due to recipients and the IRS. Form 940 (FUTA) due, and Form 941 for the fourth quarter due (with later dates if all deposits were made on time). See payroll tax deposits and filings and information returns and 1099-NEC.
• Throughout: gather year-end documents, close the books, review prior-year entity compliance.

February

• February 15 (approximately): Forms 1099-B, 1099-S, and certain 1099-MISC boxes to recipients (dates vary).
• Mid to late February: confirm year-end bookkeeping is complete and share the package with your preparer. See month-end close checklist.
• Mid-February: employees who claimed exemption from withholding must submit new W-4s (for the prior year's exemption).

March

• March 15: Form 1120-S (S-corporation) and Form 1065 (partnership) returns due, along with Schedules K-1 to owners, or extension request on Form 7004. Also the deadline to file Form 2553 for an S-corp election effective for the calendar year, or Form 8832 for entity classification effective for the year (within 75 days of the start). See S-corp election guide and S-corp tax return guide.
• March 31: electronically filed Forms 1099-MISC (other than NEC) due to the IRS, in general.

April

• April 15: individual income tax returns (Form 1040) due or extension requested (Form 4868). Form 1120 (C-corporation) due or extended. First-quarter estimated tax payment for individuals (Form 1040-ES). Deadline for prior-year IRA, HSA, and certain other contributions. Also sole proprietor self-employed retirement plan contributions (if not extended) and payment of any tax due. See estimated taxes guide.
• April 30: Form 941 for the first quarter due. Payroll state returns due in many states.

May

• May 15: exempt organization returns (Form 990 for calendar-year filers). Not applicable to most small businesses.
• Monthly: payroll tax deposits due on the 15th for monthly depositors.

June

• June 15: second-quarter individual estimated tax payment. Also, the due date of filing for U.S. citizens and residents living abroad.
• Monthly: payroll deposits.
• Mid-year checkpoint: review profit, salary, and estimated taxes.

July

• July 31: Form 941 for the second quarter due.
• Mid-year: review retirement plan design and contributions.

August

• Mid-August: no major federal deadline for most small businesses, but review bookkeeping and estimates.

September

• September 15: third-quarter individual estimated tax payment. Extended Form 1120-S and Form 1065 returns due (six months after March 15). Extended corporate returns for fiscal-year filers where applicable (calendar-year C-corps extended to October 15).
• Late September: begin year-end tax planning.

October

• October 1: deadline to establish a SIMPLE IRA for the year (for most employers). See SIMPLE IRA guide.
• October 15: extended individual returns (Form 1040) and extended C-corp returns due. Extended sole proprietor retirement plan contributions and HSA contributions may be made by this date if the return was extended (for deduction).
• October 31: Form 941 for the third quarter due.

November

• Early November: year-end planning: equipment purchases, retirement plan design, salary adjustments for S-corp owners. See setting your owner salary in an S-corp.
• Mid-November: confirm W-9s for vendors.

December

• December 31: last day for many actions that affect the tax year: paying deductible expenses (cash method), placing assets in service, adopting a solo 401(k) for employee deferrals, making S-corp payroll adjustments, taking required distributions, and completing charitable giving. See Section 179 and depreciation basics and solo 401(k) guide.
• Mid-December: run a final payroll early to allow for year-end W-2 reporting.

Recurring items

• Payroll deposits: monthly (15th) or semiweekly, depending on your schedule.
• Sales tax filings: monthly, quarterly, or annual, depending on the state and volume. See sales tax nexus basics.
• State estimated payments: often on the same schedule as federal, sometimes different.
• State annual reports and franchise taxes: dates vary widely. See annual reports and franchise taxes.
• Business license renewals and registered agent renewals.
• Insurance renewals.
• Pass-through entity tax elections and payments, if applicable. See pass-through entity tax.

How to use the calendar

1. Add the dates to a shared calendar with reminders 30 and 7 days before.
2. Assign an owner and backup for each task.
3. Adjust for your entity type: sole proprietors skip entity returns, S-corps add March 15, C-corps have April 15.
4. Note your fiscal year if not calendar.
5. Check state calendars separately.
6. Update annually, including checking for changes.

Extensions

An extension of time to file is not an extension of time to pay. For individuals, Form 4868 extends filing to October 15, but tax owed is due April 15. Entities file Form 7004 to extend by six months. Estimates and payroll deposits are not extended. If you owe and cannot pay in full, file on time and pay what you can. Penalties for failure to pay are typically lower than for failure to file.

Common mistakes

1. Confusing entity return deadlines with individual deadlines.
2. Missing the March 15 K-1 deadline, delaying owners' returns.
3. Treating estimated tax quarters as equal periods.
4. Forgetting SIMPLE IRA and solo 401(k) adoption deadlines.
5. Not calendaring state due dates.
6. Assuming an extension covers payment.
7. Skipping year-end planning until January.

For help building a calendar customized to your entities, AE Tax Advisors can assist, and a discovery call is a good first step.