S-Corp Tax Deadlines 2026: Every Date Your Business Needs to Know

Published: March 19, 2026 Tax Year: 2026

A Message from Slava

When I built Anna Money for 60,000+ small businesses in the UK, corporate tax deadlines were relatively forgiving — nine months after your accounting period ends, plus a separate deadline for the company tax return. In the US, S-Corps play by a completely different set of rules.

The biggest shock for new S-Corp owners is that your business return is due a full month before your personal return. March 16, not April 15. I've talked to dozens of business owners who missed that deadline in their first year because they assumed all tax returns were due in April. The penalty for that mistake is $235 per shareholder for every month the return is late. For a two-person S-Corp that files three months late, that's $1,410 — and the IRS isn't flexible about waiving it.

On top of that, S-Corps have payroll tax deposits (monthly or semi-weekly), quarterly 941 filings, K-1 distribution requirements, and shareholder estimated tax payments to track. Each one has its own deadline and its own penalty structure.

This guide puts every S-Corp deadline for 2026 in one place: what's due, when it's due, how much the penalty is if you miss it, and what you can extend. Bookmark it, print it, or add each date to your calendar right now.

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Executive Summary: 2026 S-Corp Deadlines at a Glance

Legal basis: IRC §6072 (time for filing), IRC §6037 (return requirement for S-Corps), IRC §6654 (estimated tax underpayment)

For an interactive version of this calendar, see the S-Corp Tax Deadline Calendar.

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Form 1120-S: The S-Corp Income Tax Return

Filing Deadline: March 16, 2026

The statutory deadline for Form 1120-S is the 15th day of the third month after the tax year ends. For calendar-year S-Corps, that's March 15. In 2026, March 15 falls on a Sunday, so the deadline shifts to Monday, March 16, 2026.

Form 1120-S reports the S-Corp's income, deductions, credits, and each shareholder's allocable share of these items. The S-Corp itself generally doesn't pay federal income tax — income passes through to shareholders via Schedule K-1. But the return must still be filed on time, and the penalty for late filing is steep.

Late Filing Penalty

The penalty under IRC §6698 is $235 per shareholder per month (or fraction of a month) the return is late, for up to 12 months. This applies whether or not any tax is owed.

The clock starts the day after the deadline and each partial month counts as a full month. Even filing one day late triggers the first month's penalty.

Extension: Form 7004

If you can't file by March 16, submit Form 7004 by the original deadline to get an automatic 6-month extension to September 15, 2026. Filing Form 7004 is straightforward — it's a one-page form. E-file it through your tax software or have your CPA submit it.

Key point: the extension gives you more time to file, not more time to pay. If the S-Corp owes any tax (for example, built-in gains tax or excess net passive income tax), that payment is still due by March 16.

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Schedule K-1: Distribution to Shareholders

Deadline: March 16, 2026

Schedule K-1 (Form 1120-S) must be provided to each shareholder by the same date the S-Corp return is due — March 16, 2026 (or September 15 if the S-Corp files an extension).

Each K-1 reports that shareholder's share of:

• Ordinary business income or loss
• Rental income or loss
• Interest, dividends, capital gains
• Section 179 deductions
• Credits (foreign tax, etc.)
• Distributions and basis adjustments

Shareholders need their K-1 to complete their personal tax returns (due April 15). If the S-Corp is late with K-1s, shareholders face a cascade: they may need to file personal extensions, estimate their K-1 income, and potentially amend later.

For a complete walkthrough of every K-1 box and where each amount goes on Form 1040, see our Schedule K-1 Guide.

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Estimated Tax Payments: Shareholder Obligations

S-Corps don't pay federal income tax at the entity level. Income passes through to shareholders, who are responsible for paying tax on their share — including through quarterly estimated tax payments.

2026 Quarterly Due Dates for Shareholders

*June 15 falls on a Sunday, so the deadline moves to Monday, June 16.

Who Must Pay Estimated Taxes

If a shareholder expects to owe $1,000 or more in tax for the year (after subtracting withholding and credits), they must make quarterly estimated payments. The safe harbor rules apply:

• 100% of prior year tax (110% if AGI exceeds $150,000) — pay this amount and you won't owe underpayment penalties regardless of 2026 income
• 90% of current year tax — pay at least 90% of what you'll actually owe

The underpayment penalty is calculated at the federal short-term rate plus 3 percentage points, applied to each quarter individually.

S-Corp Shareholder Salary vs. Distributions

If you're a shareholder-employee taking a reasonable salary, federal and state income taxes are withheld from your paycheck. Those withholdings count toward your annual tax liability and can reduce or eliminate your need for quarterly estimated payments.

However, the K-1 income above and beyond your salary (distributions) has no withholding. You'll need estimated payments to cover the tax on that portion.

State Pass-Through Entity (PTE) Elections

Several states now offer pass-through entity tax elections, where the S-Corp pays state income tax at the entity level instead of shareholders paying it individually. If your S-Corp makes a PTE election, the entity-level state tax payments follow different deadlines set by your state — not the federal estimated payment schedule.

Check your state's PTE election rules carefully. The deadlines, rates, and election procedures vary widely.

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Reasonable Salary and Payroll Tax Deadlines

Every S-Corp that has shareholder-employees must pay them a reasonable salary and handle payroll taxes. This creates its own set of recurring deadlines.

Form 941: Employer's Quarterly Federal Tax Return

Form 941 reports wages paid, tips, federal income tax withheld, and both the employer and employee shares of Social Security and Medicare taxes.

*January 31 falls on a Sunday, so the deadline shifts to February 1.

Payroll Tax Deposits

Filing Form 941 quarterly is separate from actually depositing the payroll taxes. Deposit frequency depends on your lookback period liability:

• Monthly depositors (under $50,000 in payroll taxes during the lookback period): Deposit by the 15th of the following month
• Semi-weekly depositors ($50,000 or more): Deposit within 1–3 business days of each payday
• Next-day rule: If you accumulate $100,000+ in taxes on any day, deposit by the next business day

Deposit penalties are tiered:

These penalties apply to the entire deposit amount, not just the tax owed. A $10,000 deposit that's 6 days late costs $500.

Form 940: Annual Federal Unemployment Tax (FUTA)

Deadline: February 1, 2027 (for tax year 2026; January 31 is a Sunday)

FUTA tax is 6.0% on the first $7,000 of each employee's wages, reduced by a credit of up to 5.4% for state unemployment taxes paid — making the effective rate 0.6% in most states. If your total FUTA liability exceeds $500 in any quarter, you must deposit it by the last day of the month following the quarter-end.

What Counts as Reasonable Salary

The IRS requires S-Corp shareholder-employees to receive compensation that reflects the work they perform. There's no magic formula, but the IRS looks at comparable pay for similar roles, hours worked, training and experience, and the company's financial performance.

Paying yourself too little (or nothing) to avoid payroll taxes is one of the most common S-Corp audit triggers. Use our S-Corp Salary Calculator to find a defensible salary range based on your industry, location, and revenue.

For a deeper comparison of S-Corp salary obligations versus LLC self-employment tax, see S-Corp vs LLC: Complete Tax Comparison.

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Form 2553: S-Corp Election Deadline

Deadline: March 16, 2026 (for 2026 tax year)

If your LLC or C-Corp wants to be treated as an S-Corp for tax year 2026, you must file Form 2553 no later than 2 months and 15 days after the start of the tax year. For calendar-year entities, that's March 15 — which shifts to March 16, 2026 because March 15 is a Sunday.

Election Requirements

To qualify for S-Corp status, your business must:

• Be a domestic corporation (or LLC electing corporate treatment)
• Have only allowable shareholders (individuals, certain trusts, estates — no partnerships, corporations, or non-resident aliens)
• Have no more than 100 shareholders
• Have only one class of stock
• Not be an ineligible corporation (certain financial institutions, insurance companies, DISCs)

What If You Miss the Deadline?

If you miss the March 16 deadline, your S-Corp election won't take effect until January 1, 2027. However, the IRS offers late election relief under Revenue Procedure 2013-30 if:

• You intended to make the election
• You had reasonable cause for missing the deadline
• You file within 3 years and 75 days of the intended effective date

For a step-by-step walkthrough of converting your LLC, including the election process and timing, see How to Convert Your LLC to an S-Corp.

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Extension Rules: What Extends and What Doesn't

Filing an extension is common for S-Corps — but understanding what gets extended and what doesn't will prevent costly surprises.

What Form 7004 Extends

The extension only covers the return itself and the K-1 distribution deadline. Everything else stays on its original schedule.

Impact on Shareholders

When an S-Corp extends, shareholders don't receive their K-1s until September 15. Since personal returns are due April 15, most shareholders in this situation will need to:

1. File Form 4868 for their personal return (extending to October 15)
2. Estimate their K-1 income for purposes of paying any remaining tax by April 15
3. File their personal return once they receive the K-1

This is why late S-Corp filings cascade — one late return creates a chain reaction for every shareholder. For more on how business return deadlines interact with personal filing dates, see When Are Business Taxes Due 2026.

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Common Mistakes

1. Assuming the S-Corp Deadline Is April 15

This is the single most common mistake new S-Corp owners make. Individual returns are due April 15. S-Corp returns are due a full month earlier — March 16 in 2026. The earlier deadline exists so shareholders receive K-1s in time to prepare their personal returns. If you were a sole proprietor last year and elected S-Corp status this year, update your mental calendar immediately.

2. Late K-1 Distribution Causing a Cascade

When the S-Corp misses its filing deadline, K-1s don't go out on time. Shareholders can't finish their personal returns without K-1 data. They file extensions. They estimate income (sometimes wrong). They may need to amend later. A single late S-Corp return can create compliance headaches — and professional fees — for every shareholder involved.

3. Forgetting Payroll Tax Deposits

Income tax deadlines get all the attention. Payroll tax deposits fly under the radar — until the IRS sends a penalty notice. If you're a monthly depositor, your payroll taxes are due by the 15th of the following month. Miss that date by even a week, and the penalty jumps from 2% to 5%. These are separate from your income tax return deadlines and your Form 941 quarterly filings. Three different obligations, three different deadlines.

4. Missing the Form 2553 Election Deadline

If you want S-Corp treatment for 2026, Form 2553 must be filed by March 16, 2026. There's no extension for this form. Miss it by a day, and you're taxed as a C-Corp (or disregarded entity) for the entire 2026 tax year. Late relief exists, but it requires reasonable cause documentation and IRS approval — neither of which is guaranteed.

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How Jupid Keeps Your S-Corp Deadlines on Track

Running an S-Corp means tracking payroll deposits, quarterly estimated payments, annual filings, and K-1 distributions — each with its own deadline and penalty structure. Jupid handles the financial tracking that feeds into all of those obligations.

Connect your bank accounts and Jupid automatically categorizes your income and expenses with 95.9% accuracy. Instead of scrambling at year-end to sort through twelve months of transactions, your books stay current throughout the year. When your CPA asks for your financials to prepare Form 1120-S, the data is already organized.

Jupid's WhatsApp and iMessage AI accountant gives you instant access to your financial status. Ask "What were my total distributions this year?" or "How much did I pay in payroll taxes last quarter?" and get answers pulled from your actual transactions — not estimates or guesses.

The platform tracks contractor payments for 1099 reporting, monitors your income against estimated tax thresholds, and keeps a running total of deductible expenses by category. It works through the web interface, Claude Code, and other AI tools — whatever fits your workflow.

Connect your bank to Jupid and stop rebuilding your financial picture every time a deadline approaches.

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Action Checklist

Setup (Do These Now)

• Add every deadline from the executive summary table to your calendar with 2-week and 3-day reminders
• Verify your S-Corp election is in effect (check IRS acceptance letter for Form 2553)
• Confirm your payroll deposit schedule (monthly or semi-weekly) with your payroll provider
• Register for EFTPS at eftps.gov if you haven't already
• Connect your bank accounts to Jupid for automatic transaction tracking
• Set up a reasonable salary and payroll for shareholder-employees using the S-Corp Salary Calculator

Quarterly

• Make shareholder estimated tax payments by each due date (Apr 15, Jun 16, Sep 15, Jan 15)
• File Form 941 by each quarterly deadline (Apr 30, Jul 31, Oct 31, Feb 1)
• Deposit payroll taxes on schedule (monthly by the 15th, or semi-weekly within 1–3 business days)
• Review year-to-date income to adjust remaining estimated payments

Year-End

• Prepare W-2s for shareholder-employees and any other employees (due February 2, 2027)
• Prepare 1099-NECs for contractors paid $2,000+ (due February 2, 2027)
• Gather all financial data for Form 1120-S preparation
• File Form 1120-S by March 15, 2027 (or request extension via Form 7004)
• Distribute K-1s to all shareholders by the 1120-S filing deadline
• File Form 940 (FUTA) by February 2, 2027

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Resources and Citations

IRS Publications (Official Sources)

• IRS Publication 509 — Tax Calendars (official deadline reference)
• About Form 1120-S — U.S. Income Tax Return for an S Corporation
• About Form 7004 — Application for Automatic Extension of Time
• About Form 2553 — Election by a Small Business Corporation
• About Form 941 — Employer's Quarterly Federal Tax Return
• About Form 940 — Employer's Annual Federal Unemployment (FUTA) Tax Return
• About Schedule K-1 (Form 1120-S) — Shareholder's Share of Income, Deductions, Credits

Tax Code References

• IRC §6037 — Return of S Corporation (requirement to file Form 1120-S)
• IRC §6072 — Time for filing income tax returns
• IRC §6651 — Failure to file tax return or pay tax
• IRC §6698 — Failure to file partnership/S-Corp return (the $235/month penalty)
• IRC §6654 — Failure to pay estimated income tax (underpayment penalty for individuals)
• IRC §7503 — Deadline shifts when due date falls on Saturday, Sunday, or holiday

2026 Key Numbers

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Final Thoughts

S-Corp tax compliance has more moving parts than most other entity types — an earlier filing deadline, K-1 distribution obligations, payroll taxes, and shareholder estimated payments all running on different schedules. The cost of missing any one of these is real and often automatic, with no IRS discretion involved.

Mark every deadline from this guide in your calendar today. The 15 minutes it takes now will save you hundreds — or thousands — in penalties over the course of the year.

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Disclaimer

This article provides general information about 2026 S-Corp tax deadlines and should not be considered tax advice. Deadlines shift when they fall on weekends or federal holidays, and specific deadlines may differ for fiscal-year S-Corps or businesses in special circumstances. State deadlines vary and are not covered here. For advice specific to your situation, consult with a qualified tax professional or refer to IRS Publication 509 for the official tax calendar.

Tax Year: 2026 Last Updated: March 19, 2026