Business tax deadlines: What small business owners need to know in 2025-2026

Business tax deadlines are the official IRS and state due dates for filing returns, paying taxes, and submitting required forms. They apply to all business entities, from small businesses to large corporations.

Each deadline corresponds to a specific tax form, such as Form 1120 for C corporations or Form 1065 for partnerships, and depends on your tax year. If your business follows a calendar year, your filing deadline usually falls in March or April. If you operate on a fiscal year, your due date shifts to the 15th day of the third or fourth month after your fiscal year ends.

Understanding these distinctions helps you plan tax preparation, schedule payments, and avoid penalties for late filings or underpayment.

Why small businesses need to know their business tax deadlines

Every small business owner faces a series of tax deadlines that shape cash flow and compliance. Missing a due date can trigger penalties, interest, and administrative headaches that ripple through your financial operations. 

For founders, controllers, and finance teams, understanding these deadlines early in the tax year helps you plan, manage liquidity, and avoid last-minute stress. Knowing them allows you to align bookkeeping and expense management with your tax obligations.

This guide covers every major business tax deadline for 2025 and 2026, including extensions, quarterly payments, and special rules for fiscal year filers. It also explains how we can help you stay organized, automate reminders, and keep your filings on track.

Federal business tax deadlines for 2025 and 2026

Federal deadlines depend on your entity type and whether you operate on a calendar year or a fiscal year. Below are the key IRS filing deadlines for 2026.

C corporations (Form 1120)

C corporations must file their corporate income tax return using Form 1120.

• For calendar-year filers, the due date is April 15, 2025/2026.

  • You can request a six-month tax extension by filing Form 7004, which moves your filing deadline to October 15, 2026. Any tax due must still be paid by April 15 to avoid penalties and interest.

• For fiscal-year filers, the deadline is the 15th day of the fourth month after the fiscal year ends.

  • For example, if your fiscal year-end is June 30, 2025, your tax filing deadline is October 15, 2025.

• If the due date falls on a weekend or holiday, the deadline moves to the next business day.

S corporations (Form 1120-S)

S corps are pass-through entities, meaning income flows to shareholders who report it on their individual returns.

• The tax filing deadline for S corps is Monday, March 16, 2026 (for calendar-year 2025 returns). For the 2024 tax year, it was Monday, March 17, 2025 (weekend rule). 

• If you operate on a fiscal year, your return is due the 15th day of the third month after your fiscal year ends.

• File Form 7004 to request a six-month extension (for 2024 calendar-year S corps, the extended due date is September 15, 2025).

For the following year’s return (tax year 2025 filed in 2026), the S corp deadline is March 16, 2026 (next business day since March 15 is a Sunday). The six-month extension pushes the due date to September 15, 2026. 

S corps must also issue Schedule K-1 forms to shareholders by the same date so they can report their share of business income on their personal returns.

Partnerships and LLCs (Form 1065)

Partnerships and multi-member LLCs file Form 1065, reporting income, deductions, and credits.

• The due date for calendar-year partnership returns for the 2026 filing season (tax year 2025) is Monday, March 16, 2026—the next business day because March 15 is a Sunday. For fiscal-year filers, returns are due the 15th day of the third month after the tax year ends.

• Each partner receives a Schedule K-1 showing their share of profits or losses, furnished with the Form 1065 filing.

• You can request a six-month extension using Form 7004; for calendar-year partnerships, that moves the deadline to Tuesday, September 15, 2026.

If your partnership uses a fiscal year, the same rule applies. The return is due on the 15th day of the third month after your fiscal year ends.

Sole proprietors (Schedule C)

A sole proprietorship reports business income and expenses on Schedule C, attached to the individual income tax return (Form 1040).

• The filing deadline for 2025 income (filed in 2026) is Wednesday, April 15, 2026. For last year’s 2024 income, it was Tuesday, April 15, 2025. 

• You can request a six-month tax extension to October 15 (October 15, 2025 for 2024 returns; October 15, 2026 for 2025 returns), but any tax due must still be paid by the original April deadline. File Form 4868 to request the extension. 

Sole proprietors often handle bookkeeping and tax preparation themselves or through a tax professional, making early organization critical to avoid errors.

Quarterly estimated tax payments

Businesses that expect to owe more than $500 (corporations) or $1,000 (individuals and pass-through entities) in taxes must make estimated tax payments throughout the year. These payments cover federal income tax, self-employed tax, and other obligations.

Quarterly due dates for 2025

For the 2025 tax year, the estimated tax payments are due on:

• April 15, 2025 – first quarter

• June 16, 2025 – second quarter

• September 15, 2025 – third quarter

• January 15, 2026 – fourth quarter

Quarterly due dates for 2026

• April 15, 2026 – first quarter

• June 15, 2026 – second quarter

• September 15, 2026 – third quarter

• January 15, 2027 – fourth quarter

Note that the 4th installment for C corporations is due December 15 of the tax year (Dec 15, 2025 and Dec 15, 2026).

Plus, if a due date falls on a weekend or holiday, payments are due the next business day.

Corporations make these payments through the Electronic Federal Tax Payment System (EFTPS), while individuals and pass-through entities can e-file using IRS Form 1040-ES.

Failing to make timely quarterly tax payments can result in penalties and interest, even if your final income tax return is filed on time.

Payroll taxes and employer obligations

Employers must withhold and remit payroll taxes for their employees, including Social Security, Medicare, and federal income tax. These payments fund essential programs and must be deposited regularly.

Deposit schedules

• If your total payroll tax liability during the lookback period is $50,000 or less, you deposit monthly by the 15th day of the following month.

• If your liability exceeds $50,000, you deposit semiweekly. For payroll processed on Wednesday through Friday, deposits are due by the following Wednesday. For payroll from Saturday through Tuesday, deposits are due by the following Friday.

• Form 941 (Employer’s Quarterly Federal Tax Return) reports FICA taxes and income tax withholding. It is due quarterly: April 30, July 31, October 31, and January 31.

• If your FUTA tax liability is more than $500 for a quarter, you must make a deposit by the last day of the month after the end of the quarter.

If you deposit all payroll taxes on time, you may have until the 10th day of the following month to file.

1099 and W-2 reporting deadlines

Businesses must issue Form W-2 to employees and 1099-MISC or 1099-NEC to contractors and vendors.

• Form W-2 and Form W-3 must be filed with the Social Security Administration by January 31 for all regular employees.

• If you paid an independent contractor $600 or more for services (non-employee compensation), you must file Form 1099-NEC. The deadline to file with the IRS and furnish a copy to the contractor is January 31. Form 1099-MISC is used for other payments like rent or royalties and is also generally due to recipients by January 31.

These forms report business income paid to workers and contractors. Keeping accurate bookkeeping records throughout the year simplifies tax filing and reduces the risk of errors.

Fiscal-year vs. calendar-year filers

Most small businesses follow a calendar year ending December 31. However, some corporations and partnerships adopt a fiscal year that ends on a different date.

• For calendar-year filers, deadlines typically fall in March or April.

• For fiscal-year filers, the due date is the 15th day of the third or fourth month following the end of the year.

For instance, a C-corp with a fiscal year ending June 30 must file by October 15. A partnership with the same fiscal year must file by September 15.

Choosing between a calendar year and a fiscal year affects your tax liability, cash flow, and tax preparation schedule. A tax professional can help determine which structure best suits your business needs.

Extensions and filing flexibility for 2025 and 2026

If you need more time to prepare your business tax return, the IRS allows you to request a six-month extension using Form 7004.

• For S corps and partnerships, the extension deadline is September 15, 2025, or September 15, 2026.

• For C corporations, the extension deadline is October 15, 2025, or October 15, 2026.

An extension postpones the filing deadline, but any taxes owed remain due on the original deadline. Paying by the due date prevents penalties and interest.

If your business operates in a federally declared disaster area, the IRS may automatically extend your tax deadlines. Always check the IRS disaster relief page for updates.

State and local business tax deadlines

Each state sets its own state tax filing rules. Many align with federal deadlines, but some differ. For example:

• California often grants automatic extensions for business tax returns.

• New York requires separate filings for state tax and city tax.

• Texas has franchise tax reports due May 15 each year.

Managing multiple tax calendars can be a significant challenge for small businesses, especially those operating in multiple states. Consulting your state’s department of revenue website is the best source for accurate information. A tax professional can also provide guidance on your state-specific obligations.

How to prepare for tax deadlines

Waiting until the last minute to file your business taxes increases the risk of errors, missed deductions, and late filing penalties. Getting ahead of tax deadlines is a great long-term investment in your small business, but it requires organization and proactive planning. Here’s a framework to help you get started: 

Step 1: Build your annual tax calendar

Relying on memory for your tax deadlines is a recipe for missed filings. Create a dedicated tax calendar that captures every federal, state, and local due date tied to your business entity.

• Include the annual income tax return due date so you know exactly when your main filing is due.

• Add quarterly estimated tax payment deadlines to stay current on your ongoing tax liability and avoid surprises at year-end.

• Record payroll tax deposit and filing dates to keep employee withholdings and employer contributions accurate and compliant.

• List all state tax and local tax filing deadlines that apply to your business so you never miss a jurisdiction-specific requirement.

• Note the deadlines for filing information returns such as Form W-2 and Form 1099-MISC to ensure timely reporting to the IRS and recipients.

• Set automated reminders for each of these dates well in advance, giving yourself enough time to prepare and review your filings before submission.

Set reminders for these dates well in advance to give yourself ample time for tax preparation.

Step 2: Maintain impeccable bookkeeping

Clean bookkeeping is the backbone of smooth tax preparation. Keep detailed records of all business income and expenses as they happen. Use accounting software to categorize transactions and reconcile your bank accounts each month. This process not only prepares you for tax filing but also gives you a clear picture of your company’s financial position. 

Clean records make it easier to calculate estimated tax payments and forecast your annual taxable income.

Step 3: Work with a tax professional

You can handle business tax filing on your own, but a qualified tax professional brings valuable insight. They can help you identify deductions, claim every eligible tax credit, and interpret complex tax laws. A trusted advisor also supports long-term planning, helping you manage your tax liability strategically throughout the year.

Coordinating tax deadlines with cash flow

Tax obligations directly affect liquidity. Planning for business tax payments alongside payroll, vendor invoices, and capital expenses helps prevent shortfalls.

Our dashboards give you real-time visibility into upcoming tax due dates, estimated tax payments, and payroll taxes. You can schedule payments, set reminders, and monitor balances across accounts in one platform.

This visibility helps small businesses avoid surprises and maintain compliance without disrupting operations.

Common business tax mistakes that cause penalties

Even experienced filers can miss deadlines or miscalculate payments. The most frequent errors include:

• Confusing calendar year and fiscal year due dates.

• Forgetting to issue 1099-MISC or Schedule K-1 forms.

• Missing quarterly tax payments or underpaying estimated taxes.

• Failing to file Form 7004 for an extension on time.

• Overlooking payroll taxes or state tax obligations.

The IRS imposes penalties for late filings, typically 5% of the unpaid tax liability per month, up to 25%. There is also a failure-to-pay penalty, which is typically 0.5% of the unpaid taxes per month, also up to a maximum of 25%. Staying organized and using automation tools like ours reduces these risks.

Even if you can’t afford to pay your full tax liability, you should always file your income tax return on time to avoid the higher failure-to-file penalty. The IRS offers payment plans for taxpayers who need more time to pay their tax due. For more details on specific dates, refer to the official IRS Tax Calendar.

How Rho helps you stay tax-ready all year

Managing your small business's tax deadlines doesn’t have to be stressful. We centralize financial operations for SMBs, giving you the structure and visibility to stay compliant year-round.

With Rho, you can:

• Track every due date and filing deadline in one dashboard.

• Automate estimated tax payments and payroll taxes.

• Sync transactions with accounting software for accurate bookkeeping.

• Schedule payments to the IRS or state agencies directly from your account.

• Access reports that simplify tax preparation and audits.

Don’t let tax season disrupt your business. By integrating your financial workflows, you can stay prepared for every due date on your calendar.

To see how an integrated finance platform can help you manage your tax obligations with confidence, get started with Rho.

FAQs about business tax deadlines

What is the deadline to file US business taxes?

The deadline depends on your business structure and filing year.

For 2025 (calendar-year filers): Partnerships (Form 1065) and S corps (Form 1120-S): March 17, 2025 (weekend rule). C corps (Form 1120) and sole proprietors (Schedule C on Form 1040): April 15, 2025.

For 2026 (calendar-year filers): Partnerships and S corps: March 16, 2026. C corps and sole proprietors: April 15, 2026. 

General rules: partnerships/S corps—15th day of the 3rd month; C corps/1040—15th day of the 4th month. The weekend/holiday moves to the next business day.)

What is the tax extension date for 2025 and 2026?

If you file an extension by the original due date, you get extra time to file (not to pay).

• S corps & partnerships (Form 7004): extended due Sept 15, 2025; Sept 15, 2026.

• C corps (Form 7004): extended due Oct 15, 2025; Oct 15, 2026.

• Sole proprietors (Form 4868): extended due Oct 15, 2025; Oct 15, 2026.

When should I pay estimated taxes for my business?

You should make estimated tax payments quarterly if you expect to owe $1,000 or more in federal income tax for the year. For the 2025 tax year, the deadlines are April 15, 2025; June 16, 2025; September 15, 2025; and January 15, 2026. For the 2026 tax year, the filing deadlines are as follows: April 15, 2026; June 15, 2026; September 15, 2026; and January 15, 2027. 

Note for calendar-year C corps: same first three dates; Q4 is due Dec 15 of the tax year. (Corporate rule: 15th day of the 4th, 6th, 9th, and 12th months.) 

What is the due date for corporation tax?

For C corporations using a calendar year, Form 1120 is due by April 15 of the following year (April 15, 2025, and April 15, 2026). For S corporations, the Form 1120-S is due by the 15th day of the 3rd month (March 17, 2025; March 16, 2026 for calendar-year filers).

How does using a fiscal year change my business tax deadlines?

If you use a fiscal year instead of a calendar year, your tax deadlines are based on your year-end date. For a partnership or S corp, the return is due on the 15th day of the third month after the fiscal year ends. For a C corporation, it is due on the 15th day of the fourth month following the end of the fiscal year.

What is the difference between Form W-2 and Form 1099-MISC?

Form W-2 is used to report annual wages paid to employees and the taxes withheld from them, including Social Security and Medicare. Form 1099-MISC is used to report miscellaneous payments, such as rent or royalties, to non-employees. For reporting non-employee compensation to contractors, you must use Form 1099-NEC.