Business Tax Guide: 2026 Tax Deadlines & Dates

If bookkeeping is a necessary evil, then taxes are its twin brother. Let’s face it, taxes often distract founders from focusing on core business activities and cause undue stress. Your business’s taxes are also more complex than personal taxes. Founders often miss deadlines, deductions, and credits that result in lost money and, in some cases, real consequences.
It doesn’t have to be that way!

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This business tax planning guide will walk you through everything you need to know so you receive the credits your CPA probably missed last year and ensure your business finishes tax season more prepared than ever.

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Get your financial records out! We're about to ace tax season with these business tax preparation tips. And if you'd like to just be done worrying about your business's taxes, you can get an annual tax quote from Zeni here.

What  tax return forms do I need? 

Before gathering your financial records, it's important to make sure you have the right tax *forms. Submitting the wrong forms to the IRS is a waste of time, and you may not receive  money your business is entitled to. So, here's the nitty-gritty on a few of the most essential types of federal U.S. tax forms based on your startup’s business structure: 

For C-Corporations:

• Form 1120 – Reports the income, gains, losses, deductions, credits, and figures the corporation's income tax liability.

For S-Corporations:

• Form 1120S – Reports the income, gains, losses, deductions, credits, and other domestic corporation or entity information for any tax year covered by an election to be an S-corporation.

• Schedule K-1 – Reports the income, losses, and dividends for a business or financial entity's S-corporation's shareholders; multi-member LLCs might also use this form.

For Partnerships or LLCs

• Form 1065 – Reports the income, gains, losses, deductions, credits, and other information from the operation of a partnership.

• Schedule K-1 – Partnerships and LLCs give the same form to their partners to complete before filing Form 1065.

Keep in mind that these due dates are for federal business and self-employment taxes only. Depending on where you live, you may have additional state obligations to manage.

For more information on those, consult your local state tax authority. For example, the California Franchise Tax Board (FTB) is the agency in charge of California business taxes.

When are business taxes due in 2026?

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How you formed your business will help you mark the right deadlines on your 2026 business tax calendar and give you time to start gathering materials.
Don’t take these dates lightly. If you fail to file, the IRS can penalize you 5% every month for taxes owed, just like with your personal income tax return. For example, 60 days after the filing date, the minimum penalty for late Form 1120 is $525 or 100% of the taxes owed.

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Below are the business income tax-related filing deadlines for US-based companies in the 2026 tax year (Plus, we've got a downloadable PDF version too):

January 2026

January 15, 2026

• Q4 2025 Estimated Tax Payment Due — For Individuals

February 2, 2026:‍

• File And Send W-2s To Employees — For All
• Form 1099-NEC Due — For All
• Form 940: Annual Federal Unemployment Tax Act (FUTA) Due — For All
• Provide Copy B of Form 3921 To Employees— For Corps

March 2026

March 2, 2026:

• 4th 2025 Delaware Franchise Tax Estimate and Annual Report Due — For Delaware Corps

March 16, 2026:

• Form 1120S Tax Return/Extension Due — For S-Corps (Calendar-year filers)
• Form 1065 Tax Return/ Extension Due — For Partnerships (Calendar-year filers)

April 2026

April 15, 2026:

• Form 1040 Tax Return/Extension Due — For Individuals
• Form 1120 Tax Return/Extension Due — For C-Corps
• Q1 2026 Estimated Tax Payment Due — For All
• IRA Contribution Deadline — For Individuals

June 2026

June 1, 2026:

• 1st 2026 Delaware Estimated Franchise Tax Due — For Delaware Corps
• Delaware Annual Franchise Tax Due ($300) — For LLCs and Partnerships

June 15, 2026:

• Q2 2026 Estimated Tax Payment Due — For All

September 2026

September 1, 2026:

• 2nd 2026 Delaware Estimated Franchise Tax Due — For Delaware Corps

September 15, 2026

• Q3 2026 Estimated Tax Payment Due — For All
• Extended Filing Deadline for Forms 1120S and 1065 — For S Corps and Partnerships

October 2026

October 15, 2026:

• Extended Filing Deadline for Forms 1040 and 1120 — For Individuals and C-Corps

December 2026

December 1, 2026:

• 3rd 2026 Delaware Estimated Franchise Tax Due — For Delaware Corps

December 15, 2026:

• Q4 2026 Estimated Tax Payment Due — For C-Corps (Individuals have until January 15, 2027)

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Small business tax planning top questions:

1. What financial records does my business need?

When you're unorganized, taxes are an even longer process. The key to success is staying on top of daily bookkeeping and "gathering as you go." Make sure you have a copy of every invoice and receipt for every purchase.

Here's a solid start to the financial documents to set aside for taxes. There may be other required records, but this should give you a healthy start:

• Profit & Loss Statement - Your profit and loss (P&L) statement indicates how much income you took in and how much your business lost through expenses.

• Bank & Credit Card Statements - Even though you detailed all your gains and losses, you still want to assemble monthly bank statements for all accounts.

• Invoices & Receipts - Yes, your bank statements will outline every dollar that went in and out, but you still want to provide more "evidence" of business transactions. Be sure to submit every invoice and receipt for business expenses over $75.

• Payroll Sheets - If you have employees, this is another major expense. Use your payroll software to indicate everyone's wages, deductions, and payroll taxes.

2. What deductions or credits can I claim?

Common business deductions

The best CPAs and tax professionals will quiz you on all the areas they think you'll be able to score a few tax deductions based on your business costs. Still, you should come to the table armed. Here are some common business startup deductions you might want to earmark:

• Cost Of Goods Sold – COGS covers all expenses tied to producing products or services. Use Form 1125-A to calculate and deduct COGS for certain entities.

• Depreciation and Amortization – Two methods of expensing the cost or value of business assets each year over the period of time the asset generates revenue. Take a more in-depth look here in our overview of EBITA. Use Form 4562 to claim deductions for depreciation and amortization.

• Home Office, Supplies, and Internet – This includes a percentage of square footage from the cost of your home, business-related office supplies, or a portion of your monthly home Internet bill used for business purposes.

• Payroll Expenses – Service fees paid to your payroll provider and workers' compensation insurance. Payroll taxes are also important to understand. 

• Education – If you took any courses to improve your business.

• Utilities – Any overhead expenses used to fuel your business – heating, air conditioning, electricity.

• Business Insurance – Costs of general liability insurance, cyber liability insurance, commercial property insurance, or loss-of-income insurance.

New business tax breaks

If this is your first year filing taxes for a new business, you may qualify for tax breaks specific to essential costs. Qualifying expenses fall within three key categories:

• Creating the business – Includes market research, product analysis, travel related to location selection, and more.

• Launching the business – Costs of hiring and training employees, travel expenses related to suppliers and distributors, marketing expenses, legal fees, and accounting fees. This does not include the cost of equipment, which depreciates under standard business deduction rules.

• Organizational expenses of forming the business – Incorporation paperwork, legal fees, state organization fees, accounting fees, and more.

R&D tax credit

Your company may be eligible for a Research & Experimentation Tax Credit (R&D Tax Credit) of up to $500,000 if your business spends money on research and development in the United States. Many tech companies are inherently eligible due to the nature of their business.

To see if your business qualifies, follow this 4-part test:

1. Do you have a permitted purpose? Your business must be designing and developing a new product or process, seeking to improve functionality, reliability, or quality.

2. Is your project technological in nature? The activities surrounding your project rely on engineering, biological, physical, or computer sciences principles.‍

3. Is there technological uncertainty? At the project's onset, the taxpayer must be uncertain about the method, capability, or design. Further uncertainties may occur during the project.‍

4. Is there a process of experimentation? There must be an evaluation of one or more alternatives to eliminate the technical uncertainty mentioned above.

To calculate your credit, fill out Form 6765. You may also need to complete Form 3800, General Business Credit or Form 8974, Qualified Small Business Payroll Tax Credits, depending on the elections you make. In all cases, you submit the forms along with your tax return.

3. Do you have a simple business tax preparation checklist?

Yes! We covered a lot of information today, so put everything together for you in one easy-to-use checklist. From a list of all required corporate and financial documents to making sure you have a growth plan for after you finish your taxes, we’re here to help. 

Expert tax advisors will maximize your return 

Zeni understands that missing key forms or deadlines on your business taxes can put you in real jeopardy when it comes to compliance and, ultimately, business growth. 

Our tax planning strategy entails ensuring that your books are in order from day one and before critical due dates. We simplify this process by giving you access to an entire finance team under one roof. The Zeni Tax team and your dedicated financial controller work together to deeply understand your business's finances and streamline a complex process typically operated in silos. 

Additionally, by helping you maintain accurate records for your business year-round, all the legwork is done by the time tax season comes around. No more scrambling or missing out on the money you deserve. 

Interested in learning more? Book a 1-1 consultation to see how Zeni can help you make this tax season a breeze.

Additiontal Tax Prep & Planning Support

As your business expands across states, tax and compliance quickly become more complex. Beyond federal and state income tax, you’ll face added obligations like sales tax, franchise tax, and shifting deadlines.  Zeni manages your books and core tax filings. As other specific tax needs arise, many businesses turn to specialized platforms for multi-state compliance support.

Here is a service you might consider exploring:

Sphere

Sphere is an AI-powered global tax compliance platform designed to streamline multi-state tax filings as well as international VAT and GST. It centralizes obligations across sales and use tax, while automatically updating for state-specific regulatory changes.

Why pair with Zeni: Zeni ensures your books are accurate and your tax strategy is optimized, while Sphere keeps you on top of the state-by-state compliance burden. Together, they reduce risk, save time, and give you confidence that both your financials and your filings are always covered.

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