United States / Guides / The federal tax calendar for a small business
United States · guideThe federal tax calendar for a small business
The short answer
A small business tracks four calendars at once: quarterly Form 941 (last day of the month after each quarter), the January 31 employment-tax cluster (Form 940, W-2s, 1099-NEC), the entity income tax return (March 15 for an S corporation or partnership, April 15 for a C corporation), and estimated tax payments, which run on one schedule for individuals and pass-through owners and a different one for C corporations. Every date shifts to the next business day when it lands on a weekend or federal holiday. Form 7004 buys six more months to file the entity return — never to pay.
Key facts — verified dates on each
The four clocks running at once
A business with employees and a pass-through or corporate structure runs four separate recurring calendars, each with its own rhythm and form. A common way deadlines slip is confusing which calendar a date belongs to — remembering "March 15" matters without remembering it is the S-corp and partnership date, not the 941 date or an estimated-payment date.
The four: payroll and employment tax filings (941 quarterly, 940 annually, W-2 and 1099-NEC each January), the entity income tax return (1120, 1120-S, or 1065, once a year), the extension that can follow it (Form 7004), and estimated tax payments, running all year on their own quarterly rhythm.
This guide maps all four onto one page. The 1120 and 1120-S due dates each have their own deep-dive guide with extension mechanics and late-filing penalties in full; this page is the calendar, not the penalty schedule.
Employment tax dates: 941, 940, W-2, and 1099-NEC
Form 941 reports federal income tax withheld plus Social Security and Medicare tax for a calendar quarter, due the last day of the month after the quarter ends: April 30, July 31, end of October, end of January. A business that deposited all its employment taxes on time for the quarter gets 10 additional calendar days to file the return — the deposits and the return sit on separate clocks.
Form 940 reports federal unemployment tax (FUTA) for the full calendar year and is due January 31 following the year it covers, with the same 10-day rule if FUTA deposits were all made on time.
W-2s go to employees, and copies go to the Social Security Administration, by January 31 for the prior year's wages. Form 1099-NEC — nonemployee compensation to contractors — follows the same January 31 date, to both the recipient and the IRS. When the 31st falls on a weekend it moves to the next business day: for wages and payments made in 2025, the actual due date was February 2, 2026, because January 31, 2026 fell on a Saturday.
The entity return: a month apart for pass-throughs and C corps
The three common small-business entity returns do not share a due date, and the gap is deliberate. Form 1120-S (S corporations) and Form 1065 (partnerships) are both due the 15th day of the third month after the tax year ends — March 15 for a calendar-year filer. Form 1120 (C corporations) is due a month later, the 15th day of the fourth month — April 15 for a calendar-year filer.
The reason is the Schedule K-1. An S corporation or partnership pays no entity-level federal income tax; each owner reports their share of income on their own Form 1040, using the K-1 the entity issues. Putting the pass-through return a month ahead of the individual and C-corp deadline gives owners time to receive their K-1 before their own April 15 filing date.
When the statutory date falls on a weekend or federal holiday, it moves to the next business day, the same rule that applies to every deadline on this page. For the return covering the 2025 tax year, March 15, 2026 falls on a Sunday, so the actual due date for calendar-year 1120-S and 1065 filers is Monday, March 16, 2026. April 15, 2026 falls on a weekday, so the calendar-year Form 1120 date is unaffected.
What Form 7004 extends — and what it does not
Form 7004 requests an automatic extension of time to file an entity return: six months for a calendar-year 1120, 1120-S, or 1065. Filed on or before the original due date with a reasonable estimate of any tax owed, it is granted automatically. For a calendar-year filer that pushes the 1120-S and 1065 deadline to September 15, and the 1120 deadline to October 15.
What it does not do is extend the time to pay. Any entity-level tax owed is still due on the original date; interest and a failure-to-pay penalty run from the day after that date regardless of the extension. Most pass-through entities owe no entity-level federal tax, but shareholders and partners still need a K-1 or a reliable estimate in time for their own April 15 deadline — an extended entity return does not extend an owner's personal filing date.
A business planning to extend still needs books closed enough to produce a credible estimate of what is owed — a bookkeeping question that sits ahead of the extension decision, not after it.
Estimated tax payments: two different quarterly calendars
Estimated tax runs on two different schedules depending on who is paying. Individuals — sole proprietors, partners, and S-corp shareholders paying tax on their share of pass-through income — pay on the Form 1040-ES schedule: April 15, June 15, and September 15 of the tax year, then January 15 of the following year. Filing the full return and paying the balance by February 1 lets a taxpayer skip that fourth payment.
C corporations pay on a different pattern set by the Internal Revenue Code: the 15th day of the 4th, 6th, 9th, and 12th months of the tax year — April 15, June 15, September 15, and December 15 for a calendar-year corporation. The first three dates match the individual schedule; the fourth is a December payment instead of a January one, with no early-filing grace period.
Both schedules shift to the next business day on a weekend or holiday. In 2026, none of the eight installments land on a weekend, so all fall on their statutory dates.
- A missed or underpaid installment can trigger an estimated-tax penalty, calculated separately from any return-filing penalty
Where this fits with the books
None of these dates are primarily a books problem, but nearly all depend on the books being ready before the date arrives. A 941 needs payroll records reconciled to that quarter's deposits. A K-1 needs a general ledger closed and allocated to each owner. An extension estimate needs a trial balance current enough to be a real estimate, not a guess.
CapEasy's bookkeeping work keeps that ledger current and hands a CPA a trial balance built to support these deadlines — it does not prepare, calculate, or file any return, deposit, or estimated payment named here, and does not determine what a business owes. Those stay with the business's CPA or tax preparer, who is positioned to sign what gets filed.
The figures, and when we checked them
These numbers change by year or by notification. Each one shows the date we last verified it against the source — if that date looks old, check the source before relying on it.
Questions on this
What is the first federal tax deadline of the year for a small business?
Employment-tax dates cluster at the start of the year: Form 940 and W-2/1099-NEC are due January 31 following the tax year (next business day if the 31st is a weekend), and the Form 941 return for the prior year's Q4 is due the same date.
Do all these dates move if they fall on a weekend or holiday?
Yes — every deadline here follows the same rule: a Saturday, Sunday, or federal holiday pushes it to the next business day. That is why the actual date for a given year can differ from the "15th" or "31st" people remember.
Does paying employment taxes on time change the Form 941 filing date?
It adds 10 calendar days. If every deposit for the quarter was on time, the business gets until 10 days after the normal due date to file the return — deposits and filing are tracked separately.
Why is the S-corp and partnership return due a month before the C-corp return?
Because S corporations and partnerships are pass-through entities. Owners need their Schedule K-1 to file their own Form 1040 by April 15, so the entity return — and the K-1s it generates — is due a month earlier, on the 15th day of the third month rather than the fourth.
How much extra time does Form 7004 give?
Six months for all three common entity returns: a calendar-year 1120-S or 1065 moves from March 15 to September 15, and a calendar-year 1120 moves from April 15 to October 15. It must be filed on or before the original due date.
Does an extension to file also extend the time to pay?
No. Form 7004 only extends the filing deadline. Any tax owed at the entity level is still due on the original date, with interest and a failure-to-pay penalty running from the day after that date regardless.
What are the estimated tax due dates for a sole proprietor or S-corp shareholder?
The Form 1040-ES schedule: April 15, June 15, and September 15 of the tax year, then January 15 of the following year. That fourth payment can be skipped if the full return is filed and the balance paid by February 1.
Are C-corporation estimated tax dates the same as the individual schedule?
The first three match — April 15, June 15, September 15 — but a C corporation's fourth installment is due December 15 the same year, not January 15 of the following year like the individual schedule.
Where can a business confirm the exact date for a specific year?
IRS Publication 509, Tax Calendars, and the current-year employment-tax due dates page on irs.gov. Since several dates move year to year with weekends and holidays, checking the current IRS page beats reusing a date list from a prior year.
Does CapEasy file any of these returns or make these payments?
No. CapEasy's bookkeeping work keeps the ledger current enough to support these deadlines — reconciled accounts, a trial balance a CPA can use for a return or an extension estimate. Preparing, calculating, and filing 941, 940, 1120, 1120-S, 1065, Form 7004, and estimated tax payments stays with the business's CPA or tax preparer.
Primary sources
- IRS — Publication 509, Tax Calendars
- IRS — Employment tax due dates
- IRS — Instructions for Form 7004
- IRS — 2026 Form 1040-ES, Estimated Tax for Individuals
- 26 U.S.C. § 6655 — Failure by corporation to pay estimated income tax (Cornell Legal Information Institute)
- 26 U.S.C. § 6072(b) — Time for filing income tax returns of partnerships and S corporations (Cornell Legal Information Institute)
- IRS — Instructions for Form 1120
Last reviewed 2026-08-14. Statutes and schedules change — the sources above are authoritative, this page is orientation.
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