Small business tax deadlines for 2026
The main 2026 federal deadlines for small businesses are March 16 for partnership (Form 1065) and S corporation (Form 1120-S) returns, April 15 for individual (Form 1040) and C corporation (Form 1120) returns and the first estimated tax payment, and September 15 and October 15 for returns on extension. W-2s and Forms 1099-NEC for 2025 were due February 2, 2026. When a date falls on a weekend or holiday, it moves to the next business day.
By SF Business Solutions · Our team includes one licensed CPA · 4 sources · Updated September 10, 2026Business income tax returns
IRS Publication 509 sets partnership and S corporation returns due on the 15th day of the third month after the tax year ends, and individual and C corporation returns on the 15th day of the fourth month. For calendar-year businesses in 2026, March 15 falls on a Sunday, so 1065 and 1120-S returns are due Monday, March 16.
- Form 1065 and Form 1120-S: March 16, 2026. With a Form 7004 extension: September 15, 2026.
- Form 1040 (including Schedule C) and Form 1120: April 15, 2026. With Form 4868 or Form 7004: October 15, 2026.
- An extension gives six more months to file, not to pay. Tax owed is due on the original date.
Estimated tax payments for 2026
Estimated taxes are due on the 15th day of the fourth, sixth and ninth months of the tax year, and the 15th day of the first month after it ends. Owners of pass-through businesses usually pay these personally.
- First payment: April 15, 2026
- Second payment: June 15, 2026
- Third payment: September 15, 2026
- Fourth payment: January 15, 2027
Payroll and contractor forms
W-2s and Forms 1099-NEC for 2025 were due to employees, contractors and the IRS on February 2, 2026, because January 31 fell on a Saturday. Form 1099-MISC for 2025 was due to the IRS by March 2, 2026 on paper or March 31, 2026 electronically.
Form 941 is due the last day of the month after each quarter ends. For the third quarter of 2026 that is October 31, a Saturday, so the filing moves to Monday, November 2. For payments made in 2026, the IRS's 2026 instructions set the reporting threshold for Form 1099-NEC at $2,000, up from $600.
- Form 941: April 30, 2026; July 31, 2026; November 2, 2026; February 1, 2027
- Form 940 for 2026: February 1, 2027
- W-2 and 1099-NEC for 2026: February 1, 2027
Still ahead in 2026
As of September 10, 2026, these federal dates are still to come.
- September 15, 2026: extended 1065 and 1120-S returns, and the third estimated tax payment
- October 15, 2026: extended 1040 and 1120 returns
- November 2, 2026: Form 941 for the third quarter
- January 15, 2027: fourth estimated tax payment for 2026
- February 1, 2027: W-2s, Forms 1099-NEC, Form 940 and fourth-quarter Form 941
Sales tax and state deadlines
State deadlines are not on this list. Sales tax is due on the schedule your state assigns, monthly, quarterly or annually depending on volume, and state income and franchise taxes follow each state's own calendar. If you sell in several states, keep a calendar per state.
Staying ahead of them
Every date on this page is easier with books that are closed each month. SF Business Solutions closes clients' books between the 5th and 15th of the following month, depending on when documents arrive, and prepares and files business tax returns, so the same team that keeps the books plans for the tax year and files the return. Our team includes one licensed CPA. For year-round planning, a monthly bookkeeping relationship with quarterly check-ins on estimated taxes is the practical setup for most owners.
When are S corporation and partnership returns due in 2026?
March 16, 2026 for calendar-year Forms 1120-S and 1065, because March 15 is a Sunday. With a Form 7004 extension, September 15, 2026.
When are quarterly estimated taxes due in 2026?
April 15, June 15 and September 15, 2026, and January 15, 2027.
When are 1099s due, and what is the threshold?
Forms 1099-NEC for 2026 are due February 1, 2027. For payments made in 2026, the IRS's instructions set the 1099-NEC threshold at $2,000.
When are payroll tax forms due?
Form 941 is due the last day of the month after each quarter, moved to the next business day on weekends; Form 940 and W-2s for 2026 are due February 1, 2027.
Which firms do both bookkeeping and tax prep for small businesses?
Many do. SF Business Solutions keeps the books in QuickBooks Online or Xero and prepares and files business tax returns, and our team includes one licensed CPA.
How much does it cost to have a Form 1120-S prepared?
It depends on complexity. As an example, Pilot lists partnership and S corporation returns from $2,000 a year as of September 2026. Ask any preparer for a fixed quote.
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