Tax

Small Business Tax Deadlines for 2026, By Entity Type

Every date that matters this year: the small business tax deadlines 2026 filers need for S-corps, partnerships, C-corps, and sole proprietors, plus payroll filings, 1099s, quarterly estimates, and how extensions actually work.

By Aparna Devalla, CPA4 min · 6 slidesUpdated August 2, 2026

1 / 6

The 2026 Calendar at a Glance

January 15, 2026: fourth-quarter 2025 estimated tax payment. February 2, 2026: W-2s and 1099-NEC forms due, pushed from January 31 because it falls on a Saturday.
March 16, 2026: S-corp (1120-S) and partnership (1065) returns for 2025, pushed from March 15 because it falls on a Sunday. This is also the S-corp election deadline for calendar-year 2026.
April 15, 2026: individual returns (1040), C-corp returns (1120), first-quarter 2026 estimates, and 2025 IRA and HSA contributions.
June 15 and September 15, 2026: second and third quarter estimated payments. September 15 is also the extended deadline for S-corp and partnership returns.
October 15, 2026: extended 1040 and 1120 returns. January 15, 2027: fourth-quarter 2026 estimate. Put these business tax due dates on the calendar now, with reminders two weeks ahead.

Deadlines by Entity Type

S-corps and partnerships file by March 16, 2026 for tax year 2025, a month before individual returns, because their K-1s feed the owners' 1040s.
The penalty for a late 1120-S or 1065 is charged per owner, per month, so a multi-member entity filing late runs up real dollars fast even when no tax is due with the return.
C-corps file the 1120 by April 15, 2026, and pay any tax owed by that date. The extension runs to October 15.
Sole proprietors and single-member LLCs report on Schedule C with the owner's 1040, due April 15, 2026, extendable to October 15.
Missed the March 16 window for an S-corp election? Late-election relief under Rev. Proc. 2013-30 is often available; our S-corp vs LLC guide covers whether the election is worth it at all.

Payroll and Contractor Filings

W-2s go to employees and the Social Security Administration by February 2, 2026. The same date covers 1099-NEC forms for contractors you paid $600 or more in 2025.
Quarterly payroll returns (Form 941) are due the last day of the month after each quarter ends: April 30, July 31, and November 2 (October 31 is a Saturday), plus February 2 for Q4 2025. The annual FUTA return (940) is due February 2.
Other 1099s, like 1099-MISC and 1099-INT, go to recipients in early February and to the IRS by March 31, 2026 when filing electronically.
The 1099-K reporting threshold is back to $20,000 and 200 transactions, and it is the platform's filing obligation, not yours. Your obligation is reporting all the income either way.
Payroll tax deposits run on their own semiweekly or monthly schedule set by your deposit history, and the penalties for late deposits are steep and nearly automatic. This is the strongest argument for a payroll service.

Quarterly Estimated Taxes

Owners of passthroughs and sole proprietorships prepay tax during the year. For tax year 2026, payments are due April 15, June 15, and September 15, 2026, and January 15, 2027.
The quarters are uneven on purpose: the second payment covers only April and May. Setting aside a fixed percentage of profit monthly beats scrambling at each due date.
Safe harbor stops underpayment penalties: pay in at least 100% of last year's total tax (110% for higher-income filers) in even installments, and no penalty applies regardless of what you finally owe.
Underpayment penalties accrue per quarter, so a missed June payment cannot be cured by a bigger September one. Catch up as early as possible.
Our quarterly estimated tax guide covers the calculation methods; if income arrives unevenly, the annualized installment method can match payments to when you actually earned.

How Extensions Actually Work

An extension extends the time to file, never the time to pay. Tax owed is still due at the original deadline, and interest plus late-payment penalties run on any shortfall.
Entities file Form 7004 for an automatic extension: 1120-S and 1065 move from March 16 to September 15, 2026, and 1120 moves to October 15. Individuals file Form 4868 to move the 1040 to October 15.
Estimate and pay your expected liability with the extension request. A well-funded extension costs almost nothing; an unfunded one just delays the bill while penalties accrue.
Extending is normal practice, not an audit flag, and filing an accurate extended return beats filing a rushed wrong one in every case.
The late-filing penalty is roughly ten times the late-payment penalty, so if the deadline arrives and you cannot pay, file anyway. Owing money is a payment plan; not filing is a penalty machine.

State Deadlines and Staying Ahead

Most states piggyback on the federal calendar for income tax returns, but not all, and state extensions are not always automatic with the federal one. Confirm each state where you file.
States layer on their own obligations: franchise taxes, annual reports, and LLC fees, each with its own due date. California's franchise tax calendar is a common trap; see our California franchise tax guide.
Sales tax runs on a completely separate cadence, monthly, quarterly, or annually by state and volume, and multi-state sellers can face dozens of filings a year.
Note what no longer applies: domestic companies are exempt from beneficial ownership (BOI) reporting, so that deadline is off the list for U.S.-formed entities.
Rubric Financial maintains the full federal and state deadline calendar for clients, files the extensions, and schedules the estimates, so no date on this list depends on the owner's memory.

Use ← → keys, or swipe on mobile

Educational content, not tax, legal, or accounting advice. Confirm with a CPA before acting.

Frequently asked questions

When are business tax returns due in 2026?

S-corp (1120-S) and partnership (1065) returns for tax year 2025 are due March 16, 2026, since March 15 falls on a Sunday. C-corp (1120) returns and individual returns reporting sole proprietorships are due April 15, 2026. With extensions, S-corps and partnerships get until September 15, 2026, and C-corps and individuals until October 15, 2026. Payment is always due at the original deadline regardless of extension.

When are 1099s due in 2026?

1099-NEC forms for contractors paid $600 or more in 2025 are due to both recipients and the IRS by February 2, 2026, because January 31 falls on a Saturday. Other varieties like 1099-MISC and 1099-INT go to recipients in early February and to the IRS by March 31, 2026 if filed electronically. The 1099-K threshold for payment platforms is $20,000 and 200 transactions, and that filing belongs to the platform, not to you.

When are quarterly estimated taxes due in 2026?

For tax year 2026: April 15, June 15, and September 15, 2026, with the fourth payment due January 15, 2027. The final 2025 payment was due January 15, 2026. The quarters are intentionally uneven, so the June payment covers just two months of income. To avoid underpayment penalties, use the safe harbor: pay at least 100% of last year's total tax, or 110% for higher-income filers, in even installments.

Does filing a tax extension extend the time to pay?

No. Extensions move only the filing deadline, never the payment deadline. You should estimate your liability and pay it with the extension request (Form 7004 for entities, Form 4868 for individuals); interest and late-payment penalties accrue on any unpaid balance from the original due date. A funded extension is cheap and routine. And if you cannot pay, still file on time, because the late-filing penalty dwarfs the late-payment penalty.

What happens if I miss a business tax deadline?

File as soon as possible, because penalties compound monthly. Late S-corp and partnership returns are penalized per owner per month even when no tax is due. Late individual and C-corp filings face a late-filing penalty that is roughly ten times the late-payment penalty, plus interest. First-time penalty abatement is often available for taxpayers with a clean three-year history, so a single slip is usually fixable; a pattern is not.

Accounting

Back to all resources

Need help applying this to your business?

Talk to a partner at Rubric Financial, one business day response. We'll scope a plan tailored to your situation, with a fixed monthly fee.

Small Business Tax Deadlines for 2026, By Entity Type

The 2026 Calendar at a Glance

Deadlines by Entity Type

Payroll and Contractor Filings

Quarterly Estimated Taxes

How Extensions Actually Work

State Deadlines and Staying Ahead

Frequently asked questions

When are business tax returns due in 2026?

When are 1099s due in 2026?

When are quarterly estimated taxes due in 2026?

Does filing a tax extension extend the time to pay?

What happens if I miss a business tax deadline?

When (and How) to Switch From Cash to Accrual Accounting

Month-End Close Checklist for Small Businesses

Multi-State Payroll Setup for Small Businesses

Need help applying this to your business?

Small Business Tax Deadlines for 2026, By Entity Type

The 2026 Calendar at a Glance

Frequently asked questions

When are business tax returns due in 2026?

When are 1099s due in 2026?

When are quarterly estimated taxes due in 2026?

Does filing a tax extension extend the time to pay?

What happens if I miss a business tax deadline?

You might also like

When (and How) to Switch From Cash to Accrual Accounting

Month-End Close Checklist for Small Businesses

Multi-State Payroll Setup for Small Businesses

Need help applying this to your business?