The IRS business tax forms you file depend on three things: how your business is legally organized, whether you pay employees, and whether you pay independent contractors or excise-taxed goods. For most small businesses, that means one annual income tax return, quarterly estimated payments, and, if you have workers, a stack of payroll and information returns with their own separate deadlines. This guide walks through the forms by category and gives you the 2026 due dates for each.
Which Annual Income Tax Return You File
Your legal structure decides the form. Filing the wrong one gets your return rejected.
Sole Proprietors and Single-Member LLCs
If you haven’t formed a separate entity, or you own a single-member LLC, you report business income and expenses on Schedule C attached to your personal Form 1040. Schedule C captures gross receipts, cost of goods sold, and operating expenses to produce a net profit or loss that flows onto your individual return.1Internal Revenue Service. About Schedule C (Form 1040), Profit or Loss from Business (Sole Proprietorship) That net profit is also subject to self-employment tax at a combined 15.3% rate, reported on Schedule SE.2Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes)
The Form 1040 due date for calendar-year filers is April 15, 2026. Form 4868 buys an automatic six-month extension to October 15, but only for filing. Any tax you owe is still due April 15.
C Corporations
A C corporation is a separate taxpayer and files Form 1120. The corporation pays federal income tax at a flat 21% rate, and shareholders only face personal tax when dividends are distributed.3Internal Revenue Service. About Form 1120, U.S. Corporation Income Tax Return
For a calendar-year C corporation, Form 1120 is due by the 15th day of the fourth month after year-end. That’s April 15, 2026 for most filers.4Internal Revenue Service. Publication 509 (2026), Tax Calendars Missing the deadline triggers a failure-to-file penalty of 5% of unpaid tax per month or partial month, capped at 25%.5Internal Revenue Service. Failure to File Penalty
S Corporations and Partnerships
S corporations file Form 1120-S; partnerships file Form 1065. Neither entity pays federal income tax directly. Income, deductions, and credits pass through to the owners on Schedule K-1, and the owners report those amounts on their personal returns.6Internal Revenue Service. About Form 1065, U.S. Return of Partnership Income7Internal Revenue Service. About Form 1120-S, U.S. Income Tax Return for an S Corporation
Both returns are due by the 15th day of the third month after year-end. For 2025 calendar-year filers, that date is March 15, 2026, a Sunday, which pushes the deadline to Monday, March 16, 2026.4Internal Revenue Service. Publication 509 (2026), Tax Calendars File on time. Partners and shareholders need their K-1s to finish their personal returns by April 15.
Estimated Tax Payments Throughout the Year
If your business expects to owe $1,000 or more in tax for 2026 after withholding and refundable credits, you generally have to make quarterly estimated payments instead of waiting until the annual return.8Internal Revenue Service. 2026 Form 1040-ES, Estimated Tax for Individuals Corporations use Form 1120-W to calculate estimates. Sole proprietors and partners use Form 1040-ES.
The 2026 quarterly due dates:
- 1st payment: April 15, 2026
- 2nd payment: June 15, 2026
- 3rd payment: September 15, 2026
- 4th payment: January 15, 2027
You can skip the January 15 installment if you file your 2026 return and pay the full balance by February 1, 2027.8Internal Revenue Service. 2026 Form 1040-ES, Estimated Tax for Individuals Underpayments trigger a quarterly-calculated penalty at the federal short-term rate plus three percentage points, compounded daily.9Internal Revenue Service. Quarterly Interest Rates
Payroll Forms If You Have Employees
Employers file a separate set of returns for wages and payroll taxes. Mistakes here carry the harshest consequences in the entire tax code, because the IRS treats withheld employee taxes as trust funds.
Form 941 Every Quarter
Form 941 reports federal income tax withheld from paychecks plus the employee and employer shares of Social Security and Medicare taxes.10Internal Revenue Service. About Form 941, Employer’s Quarterly Federal Tax Return Deposits themselves follow a semiweekly or monthly schedule based on payroll size; the form reconciles what was deposited against what was owed.
Under IRC 6672, any person responsible for collecting and paying over withheld payroll taxes who willfully fails to do so can be held personally liable for the full amount. This is the Trust Fund Recovery Penalty.11Office of the Law Revision Counsel. 26 USC 6672 – Failure to Collect and Pay Over Tax, or Attempt to Evade or Defeat Tax “Responsible person” is read broadly and can reach corporate officers, bookkeepers, and even volunteer board members with financial authority.
Form 940 Annually for Unemployment Tax
Form 940 reports Federal Unemployment Tax (FUTA). The statutory rate is 6.0% on the first $7,000 of wages per employee, but employers who pay state unemployment taxes on time get a credit of up to 5.4%, bringing the effective FUTA rate down to 0.6%. That works out to a maximum of $42 per employee per year.12Internal Revenue Service. FUTA Credit Reduction Form 940 is due January 31 following the tax year. If you deposited all FUTA owed on time, you get an extra ten days.
Forms W-2 and W-3 for Employee Wages
At year-end you must furnish a Form W-2 to every employee and file copies with the Social Security Administration along with transmittal Form W-3. For the 2025 tax year, both deadlines fall on February 2, 2026.13Internal Revenue Service. Topic No. 752, Filing Forms W-2 and W-3 This is earlier than most other returns and catches employers off guard.
Form 1099-NEC for Contractor Payments
If your business pays $600 or more to an independent contractor, freelancer, or other non-employee for services during the year, you report it on Form 1099-NEC.14Internal Revenue Service. Am I Required to File a Form 1099 or Other Information Return Copies go to the payee and to the IRS by January 31 following the tax year. There is no automatic extension for this form.15Internal Revenue Service. Instructions for Forms 1099-MISC and 1099-NEC
Before you file, be sure the worker actually is a contractor. Misclassifying an employee as a contractor creates payroll tax liability that far exceeds any 1099 penalty.
Excise and Heavy-Vehicle Forms
Most small businesses never touch these, but a few industries do. Form 720, the Quarterly Federal Excise Tax Return, covers fuel taxes, environmental taxes, communications taxes, and the gas guzzler tax on certain vehicle manufacturers.16Internal Revenue Service. About Form 720, Quarterly Federal Excise Tax Return
If you operate heavy highway vehicles with a taxable gross weight of 55,000 pounds or more, Form 2290 reports the Heavy Highway Vehicle Use Tax. A tax suspension is available for vehicles expected to travel fewer than 5,000 miles during the period, or 7,500 miles for agricultural vehicles.17Internal Revenue Service. About Form 2290, Heavy Highway Vehicle Use Tax Return
Extensions With Form 7004 or 4868
Form 7004 grants an automatic six-month extension for most business income tax returns, including Forms 1120, 1120-S, and 1065.18Internal Revenue Service. About Form 7004, Application for Automatic Extension of Time to File Certain Business Income Tax, Information, and Other Returns Sole proprietors filing Schedule C use Form 4868 to extend their Form 1040.
“Automatic” means the IRS doesn’t weigh your reason. File the extension by the original due date and it’s granted. But an extension of time to file is not an extension of time to pay. Estimate what you owe and send that payment with the extension form. Underpay and you’ll owe interest from the original due date plus a possible late-payment penalty.
How to Submit Your Returns
The IRS accepts business returns electronically or by paper, and is steadily pushing filers toward e-file. Corporations with $10 million or more in assets that file at least 250 returns per year are required to e-file Forms 1120 and 1120-S.19Internal Revenue Service. E-File for Large Business and International (LBI) Below those thresholds, e-filing through IRS-approved software still delivers faster acknowledgment and fewer transcription errors than paper.20Internal Revenue Service. Modernized e-File (MeF) Overview
If you file by mail, the correct address depends on the form and your state. The IRS lists mailing addresses by form type at irs.gov/filing; verify before you mail, because a return sent to the wrong processing center can be delayed by weeks.21Internal Revenue Service. Where to File Paper Tax Returns With or Without a Payment Use USPS Certified Mail or a Certificate of Mailing so you have a dated record. The postmark is your legal filing date if a deadline is ever disputed.22United States Postal Service. Mailing Your Tax Return
How Long to Keep the Records
The IRS can audit returns for at least three years from the filing date. If the agency suspects income was underreported by more than 25%, that window extends to six years. Employment tax records should be kept at least four years. If a return was never filed or involved fraud, there is no time limit on IRS enforcement.
A workable rule: keep business tax records and supporting documents for seven years. Keep records tied to property, including purchase price, improvements, and depreciation, for as long as you own the asset plus seven years after you dispose of it. Copies of the filed returns themselves are worth keeping indefinitely.