2026 Small Business Tax Calendar: What to Know and How to Stay Ahead
Tax deadlines aren’t just dates on a calendar—they’re decision points that affect cash flow, compliance, and stress levels throughout the year. Whether you’re a sole proprietor, partnership, or corporation, knowing what’s coming allows you to plan instead of react.
Below is a breakdown of the key 2026 small business tax deadlines, along with context on why they matter and who they apply to.
January: Tax Season Begins
Tax season for 2025 returns is expected to open in late January 2026. This is when the IRS begins accepting returns and when missing documents or unresolved issues from the prior year tend to surface.
January 15, 2026
Fourth-quarter estimated tax payments are due for individuals and corporations. This is the final estimate for the 2025 tax year and often catches people off guard after the holidays.
January 31, 2026
This is one of the busiest compliance dates of the year:
Forms 1099-NEC and 1099-MISC must be provided to recipients and filed with the IRS
Forms 940, 944, and 945 are due for applicable employers
Missing this deadline can result in penalties, even if no tax is owed.
February: Payroll & Information Return Follow-Ups
February 10, 2026
An extended deadline applies for certain payroll forms (940, 941, 943, 944, and 945) only if all taxes were deposited on time.
February 15, 2026
Form 1099-B must be sent to recipients.
February 28, 2026
Paper filing deadline for Form 1099-MISC with the IRS.
March: S-Corps and Partnerships
March 15, 2026
This is a critical date for:
S-corporations (Form 1120-S)
Partnerships and multi-member LLCs (Form 1065)
Schedule K-1s must also be issued to shareholders and partners so they can file their personal returns. Delays here often create a domino effect for individual filings.
March 31, 2026
Electronic filing deadline for Form 1099-MISC.
April: A Big One for Many Businesses
April 15, 2026
This date applies to:
C-corporations (Form 1120)
Sole proprietors (Schedule C with Form 1040)
First-quarter estimated tax payments for individuals and corporations
Even if you plan to extend, payment is still due by this date.
Mid-Year Estimated Payments
June 15, 2026
Second-quarter estimated tax payments are due.
September 15, 2026
Third-quarter estimated payments are due, and this is also the extended filing deadline for S-corporation and partnership returns if an extension was filed.
Fall Extensions
October 15, 2026
Extended deadline for individual and C-corporation returns.
Year-End Planning
Year-End Tax Planning
We do these proactive appointments throughout the year, but most people take advantage of them in Q4. Drop off your numbers and we’ll review them and schedule a review call to discuss year-end planning ideas.
December 15, 2026
Fourth-quarter estimated tax payments are due for corporations only. This is often a key point for year-end tax planning and cash flow decisions.
January 15, 2027
Individual estimated payments are due for Q4 of 2026 by January 15. We recommend paying these by Dec 31 now so the IRS doesn’t misclassify the payment to the wrong year. Something they’ve done repeatedly recently.
A Note on Due Dates
If a tax deadline falls on a Saturday, Sunday, or legal holiday, the due date moves to the next business day.
Final Thoughts
Not every deadline applies to every business—but missing the ones that do can be costly. A proactive approach throughout the year makes tax season smoother and allows for better planning, not just compliance.
If you’re unsure which deadlines apply to your business or want help building a system to stay ahead of them, we’re here to help. Contact us below:
— Steinke & Company
