A missed tax deadline can do more than create a rushed filing week. It can lead to penalties, interest, cash-flow pressure, and a difficult conversation with the IRS or California tax agencies. If you are asking, “when are business taxes due,” the answer depends on how your business is taxed, whether you have employees, and whether you need to make estimated payments during the year.
For Fresno and Central Valley business owners, the most useful approach is to treat tax deadlines as part of regular financial management, not as a once-a-year event. Accurate books make it easier to see what is due, set funds aside, and file with confidence.
When Are Business Taxes Due by Entity Type?
Federal business income tax return deadlines generally follow the business’s tax classification. The dates below apply to calendar-year businesses filing 2025 returns in 2026. If your business uses a fiscal year, your due date will be different.
Sole proprietors and single-member LLCs
A sole proprietor reports business income and expenses on Schedule C with their individual Form 1040. Many single-member LLCs are taxed the same way unless they have elected corporate tax treatment. For the 2025 tax year, the federal return is due April 15, 2026.
This deadline also applies to the owner’s individual return. If you expect to owe tax, remember that any balance due must be paid by April 15, even if you file an extension.
Partnerships and multi-member LLCs
Partnerships and multi-member LLCs taxed as partnerships generally file Form 1065. Their returns are usually due on the 15th day of the third month after the end of the tax year. For a calendar-year partnership, the 2025 return is due March 16, 2026, because March 15 falls on a Sunday.
The partnership itself typically does not pay federal income tax. Instead, it provides each owner with a Schedule K-1 showing their share of income, deductions, and credits. Filing on time matters because partners need those K-1s to prepare their own returns by the April deadline.
S corporations
Calendar-year S corporations file Form 1120-S, also due March 16, 2026, for the 2025 tax year. Like partnerships, S corporations issue Schedule K-1s to shareholders.
S corporation owners should pay particular attention to payroll and reasonable compensation requirements. Owner wages, payroll tax deposits, Form W-2 reporting, and income tax filing all need to work together. A return filed on time does not correct payroll compliance problems that were ignored during the year.
C corporations
A calendar-year C corporation files Form 1120. For the 2025 tax year, the due date is April 15, 2026. Unlike pass-through businesses, a C corporation generally pays income tax at the corporate level.
Corporations may also need to make estimated tax payments during the year. That means the annual filing date is only one part of the company’s tax calendar.
Estimated Tax Payments Follow Their Own Schedule
Business owners often owe tax before the annual return is due. Sole proprietors, partners, LLC members, and S corporation shareholders commonly make quarterly estimated tax payments when income is not fully covered by payroll withholding.
For 2026 individual estimated federal taxes, the standard payment dates are April 15, June 15, September 15, and January 15, 2027. These payments generally cover income tax and self-employment tax. California estimated tax payment requirements may also apply.
The right amount is not always obvious, especially when revenue changes from season to season. A contractor with a strong summer, a retailer with a busy holiday period, or a growing delivery company may need to adjust estimates rather than relying on last year’s numbers. Underpaying can result in penalties even if you pay the full remaining balance with your return.
C corporations typically have a separate federal estimated tax schedule, with payments generally due on the 15th day of the fourth, sixth, ninth, and twelfth months of their tax year. Corporate tax planning should be reviewed early, particularly when profits are increasing.
Extensions Give You More Time to File, Not More Time to Pay
An extension can be helpful when records are incomplete, a K-1 has not arrived, or a major transaction needs careful review. But an extension does not postpone the deadline to pay expected tax.
Sole proprietors and single-member LLCs can generally request an automatic extension with Form 4868. Partnerships, S corporations, and C corporations generally request extensions using Form 7004. For calendar-year partnerships and S corporations, an extension usually moves the filing deadline from March 16 to September 15, 2026. For many calendar-year individual and C corporation returns, it moves the filing deadline from April 15 to October 15, 2026.
Estimate your tax as accurately as possible and pay by the original deadline. Filing later with an approved extension can prevent a late-filing penalty, but interest and penalties may still apply to unpaid tax.
Do Not Overlook Payroll and Information Return Deadlines
If you have employees, taxes are not limited to income tax returns. Payroll tax deposits may be due monthly or semiweekly, depending on your deposit schedule and payroll tax history. The timing is strict, so waiting until the quarterly return is due is not an option.
Employers generally file Form 941 quarterly to report federal income tax withholding and Social Security and Medicare taxes. For 2026, the standard due dates are April 30 for the first quarter, July 31 for the second quarter, November 2 for the third quarter because October 31 falls on a Saturday, and February 1, 2027, for the fourth quarter because January 31 falls on a Sunday.
Year-end reporting requires special attention. Forms W-2 and most Forms 1099-NEC are generally due to recipients and the IRS by February 1, 2027, for 2026 payments and wages. Missing or incorrect taxpayer identification numbers can create filing problems, so collect and verify vendor information before year-end rather than chasing it in January.
California Business Tax Dates May Add Another Layer
California businesses may have filing and payment responsibilities with the Franchise Tax Board, the Employment Development Department, the Department of Tax and Fee Administration, or more than one agency. The requirements depend on your entity, payroll, taxable sales, and location.
For many calendar-year California corporations, the state return is due April 15. California S corporations and partnerships generally have a March filing deadline, similar to their federal deadlines. Many California entities are also subject to an annual minimum franchise tax, commonly $800, although exceptions and first-year rules can apply depending on the entity type.
Businesses that sell taxable goods may need to file sales and use tax returns monthly, quarterly, or annually. Employers have California payroll tax deposits and wage reporting obligations that can differ from federal rules. Local business licenses and industry-specific taxes can create additional dates as well.
Because California requirements can change based on registration status and business activity, do not assume a federal extension automatically resolves state obligations. Review each agency’s filing and payment requirements for your business.
Build a Tax Calendar Around Your Actual Business
A generic deadline list is a good starting point, but it is not a complete compliance plan. A business with no employees and one owner has a very different calendar than an S corporation with ten employees, regular subcontractors, sales tax filings, and multiple owners.
Start by confirming how your entity is taxed, then identify every return, deposit, and estimated payment that applies. Set reminders at least two weeks before each deadline. More importantly, schedule monthly bookkeeping so your income, expenses, payroll records, and balance sheet are current before tax due dates arrive.
Keep a separate tax savings account if cash flow allows. Many owners find it easier to move a percentage of each payment received into that account than to find a large tax payment at quarter-end. The appropriate percentage depends on your profit margin, entity structure, deductions, payroll withholding, and other household income.
SBA Accounting & Tax Solutions helps business owners turn these deadlines into an organized routine through bookkeeping, tax preparation, planning, and responsive guidance. When your records are current and your tax calendar reflects your real operations, tax deadlines become manageable business decisions rather than last-minute emergencies.
