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When Do I File Business Taxes? Key Deadlines for 2026

Published April 2026

Missing tax deadlines is expensive. Late payments trigger penalties and interest, and missing quarterly estimated tax payments can create substantial unexpected bills at year-end. Here are the critical tax filing deadlines for 2026 that every business owner must know.

April 15, 2026: Individual Tax Return Deadline

Most businesses and individual filers must file their 2025 tax returns by April 15, 2026. This includes sole proprietors, freelancers, and partnerships. If you cannot file by this date, you can request an extension, but extensions only extend the filing deadline, not the payment deadline. If you owe taxes, pay by April 15 to avoid penalties and interest.

April 15, 2026: First Quarter Estimated Tax Payment

Self-employed individuals and business owners who owe estimated taxes must make their first quarterly payment for 2026 by April 15. This payment covers income and self-employment taxes for the first quarter.

June 15, 2026: Second Quarter Estimated Tax Payment

Your second quarterly estimated tax payment is due June 15, 2026. If you have not already, check your projected income and expenses for the year and calculate your estimated tax liability.

September 15, 2026: Third Quarter Estimated Tax Payment

The third quarterly payment deadline is September 15, 2026. If your income has fluctuated significantly during the year, this is a good time to revise your estimated tax liability and adjust your final quarter payment.

January 15, 2027: Fourth Quarter Estimated Tax Payment

Your final quarterly estimated tax payment for 2026 is due January 15, 2027. This covers income from October through December.

Payroll Tax Deposits

If you have employees, you must deposit payroll taxes (federal income tax withholding, Social Security, and Medicare) regularly. Deposit schedules vary based on the size of your payroll. Employers must deposit payroll taxes either monthly or semi-weekly, depending on their total tax liability. Missing payroll tax deposits results in severe penalties.

Quarterly Payroll Tax Returns (Form 941)

Employers must file quarterly payroll tax returns by the 15th day of the month following the end of the quarter: April 30, July 31, October 31, and January 31. Form 941 reports federal income tax withheld, Social Security and Medicare taxes.

Annual Payroll Tax Return (Form 940)

Employers must file the annual federal unemployment tax return (Form 940) by January 31, 2027, for 2026 payroll. This is separate from quarterly filings.

January 31, 2027: W-2 and 1099 Reporting

If you have employees, you must issue W-2 forms by January 31, 2027. If you paid contractors or vendors $600 or more, you must issue 1099 forms by the same date. You must also file copies with the Social Security Administration and IRS.

State and Local Deadlines

Many states have their own business tax filing deadlines, sales tax deadlines, and payroll tax deadlines. These vary by state, so check with your state's revenue department for specific requirements. Some states require monthly sales tax deposits, others quarterly.

Partner and S-Corp Returns

Partnerships and S-Corporations must file Form 1065 and Form 1120-S by March 15, 2027. These business entities file separate returns even though the income passes through to owners' individual returns.

Plan Ahead

Do not wait until the deadline to prepare. Start gathering receipts, reconciling accounts, and working with your accountant in advance. Late preparation often means mistakes, missed deductions, and unnecessary stress.

The best strategy is to work with a professional bookkeeper and accountant who tracks these deadlines and ensures timely filings and payments throughout the year.