Missing a tax deadline doesn’t just mean a late filing — it means IRS penalties, interest charges, and unnecessary stress. For US small business owners, there are more deadlines throughout the year than most people realize: quarterly estimated taxes, payroll deposits, sales tax filings, 1099s, W-2s, and annual returns all have their own due dates.
This calendar covers every major federal tax deadline for US small businesses in 2026, organized by month so you can plan ahead. Bookmark it, share it with your accountant, and check it every quarter.
Quick Reference: Key 2026 Tax Deadlines at a Glance
January 2026
January 15 — Q4 2025 Estimated Tax Payment Due
If you pay quarterly estimated taxes (which you should if you expect to owe $1,000 or more at year-end), your final payment for 2025 is due today. This covers income earned October 1 – December 31, 2025.
Who pays: Sole proprietors, LLC members, S-Corp shareholders, partners in partnerships — anyone without enough withholding to cover their annual tax bill.
January 31 — W-2s and 1099-NECs Due to Recipients
If you paid any employees in 2025, their W-2 forms must be delivered by January 31. If you paid any contractor $600 or more in 2025, their 1099-NEC must also be delivered by January 31. Our payroll service handles all W-2 and 1099 preparation so you never miss this deadline.
Penalty: $60–$310 per form depending on how late. Intentional disregard: $630+ per form.
February 2026
February 28 — Paper 1099 Forms Due to IRS
If you’re filing paper 1099 forms (not recommended — e-filing is easier and gives you more time), they must reach the IRS by February 28. This covers 1099-NEC, 1099-MISC, 1099-INT, 1099-DIV, and others.
March 2026
March 15 — S-Corp and Partnership Tax Returns Due
This is one of the most commonly missed deadlines. S-Corporations (Form 1120-S) and Partnerships (Form 1065) must file their federal tax returns by March 15 — one month earlier than individual returns.
This matters because S-Corp and Partnership returns generate Schedule K-1 forms, which partners and shareholders need to complete their personal tax returns by April 15. If your S-Corp or partnership is late, your personal return may be delayed too.
Need more time? File Form 7004 for an automatic 6-month extension to September 15.
March 31 — Electronic 1099 Forms Due to IRS
If you’re e-filing your 1099 forms (which you should be — it’s faster and cheaper), March 31 is your deadline for submitting to the IRS. Use the IRS FIRE system or a service like Track1099, Tax1099, or your payroll software.
April 2026
April 15 — Individual and Sole Proprietor Tax Returns Due
The most well-known tax deadline. Sole proprietors, single-member LLC owners, and freelancers file their business income on Schedule C attached to Form 1040. Both are due April 15.
If your books aren’t ready, file Form 4868 for an automatic 6-month extension to October 15. Important: an extension gives you more time to file, not more time to pay. If you expect to owe tax, estimate and pay by April 15 to avoid underpayment penalties.
The best way to be ready by April 15? Clean monthly bookkeeping throughout the year means your CPA has everything they need in January rather than scrambling in April.
April 15 — Q1 2026 Estimated Tax Payment Due
Your first quarterly estimated tax payment for 2026 covers income earned January 1 – March 31. Use IRS Form 1040-ES to calculate and pay online at IRS Direct Pay — it’s free and instant.
Safe harbor rule: Pay either 100% of last year’s tax liability (110% if your AGI was over $150,000) or 90% of this year’s expected tax — whichever is smaller.
April 15 — C-Corp Tax Returns Due (Form 1120)
C-Corporations file Form 1120 by April 15. File Form 7004 for an automatic 6-month extension to October 15.
June 2026
June 16 — Q2 2026 Estimated Tax Payment Due
Your second quarterly payment covers income earned April 1 – May 31. Note the Q2 payment window is shorter — only two months of income. Pay via IRS Direct Pay or EFTPS.
September 2026
September 15 — Q3 2026 Estimated Tax Payment Due
The third quarterly payment covers income earned June 1 – August 31. If your business has a strong summer, this may be your largest quarterly payment.
September 15 — Extended S-Corp and Partnership Returns Due
If you filed Form 7004 in March, September 15 is the final extended deadline. No further extensions are available after this date.
October 2026
October 15 — Extended Individual and Sole Proprietor Returns Due
If you filed Form 4868 in April, October 15 is your final deadline for Form 1040. There is no further extension. Make sure your books are finalized and your CPA has everything they need well before this date.
December 2026
December 31 — Year-End Planning Deadline
December 31 is the last day to take actions that affect your 2026 tax return: buying equipment (Section 179), making retirement contributions, charitable giving, and accelerating or deferring income. After midnight, your 2026 tax year is closed.
Ongoing: Payroll Tax Deposit Deadlines
In addition to the annual and quarterly deadlines above, employers have payroll tax deposit obligations throughout the year:
Missing payroll deposit deadlines triggers immediate IRS penalties — starting at 2% for deposits 1–5 days late and rising to 15% after IRS notice.
State Sales Tax Deadlines
If your business collects sales tax in one or more US states, you have additional filing obligations that vary by state and volume:
- Monthly filers: Due the 20th of the following month
- Quarterly filers: Due April 20, July 20, October 20, and January 20
- Annual filers: Low-volume sellers may file once a year
Since the Supreme Court’s South Dakota v. Wayfair decision in 2018, businesses must collect and remit sales tax in any state where they exceed that state’s economic nexus threshold — typically $100,000 in sales or 200 transactions per year. Our tax services include multi-state sales tax compliance for clients who sell across state lines.
How to Never Miss a Deadline
The most reliable way to stay on top of tax deadlines is to work with a bookkeeper who tracks them for you. Here’s what we do for clients at Cloud Accountants:
- Send deadline reminders 30 days before each quarterly payment
- Deliver clean, reconciled books by the 10th of every month
- Prepare and file 1099-NEC forms in January for all clients with contractors
- Coordinate with your CPA so they have everything before March 15 and April 15
- Monitor payroll tax deposits to ensure compliance and avoid penalties
Frequently Asked Questions
What happens if I miss an estimated tax payment?
You’ll owe an underpayment penalty — currently around 8% annualized on the unpaid amount. If you miss Q1 or Q2, make a larger payment at the next deadline to reduce the penalty. Use IRS Form 2210 when filing to calculate the exact amount owed.
Can I get an extension on my business tax return?
Yes. File Form 7004 (for business returns) or Form 4868 (for personal returns) by the original deadline for an automatic 6-month extension. Remember: extensions apply to filing, not paying. Estimate and pay by the original deadline to avoid penalties.
I’m an LLC — which tax deadline applies to me?
It depends on how your LLC is taxed. Single-member LLCs taxed as sole proprietors file Schedule C with Form 1040 by April 15. Multi-member LLCs taxed as partnerships file Form 1065 by March 15. LLCs that elected S-Corp status file Form 1120-S by March 15. Have questions? Check our FAQ page or book a free call.
What are the penalties for late payroll tax deposits?
IRS payroll deposit penalties: 2% if 1–5 days late, 5% if 6–15 days late, 10% if more than 15 days late, and 15% after receiving an IRS notice. The Trust Fund Recovery Penalty (100% of unpaid amount) can be assessed personally against business owners who willfully fail to deposit withheld taxes.
Do I need to pay quarterly taxes if I’m just starting my business?
If you expect to owe $1,000 or more in federal tax for the year, yes. New businesses often underestimate this. If your business is profitable and you’re not having taxes withheld from a separate employer paycheck, start making quarterly estimated payments from Q1.
Save These Dates Now
Set these as recurring calendar reminders:
- January 15 — Q4 estimated tax
- January 31 — W-2 and 1099-NEC deadline
- March 15 — S-Corp and Partnership returns
- April 15 — Personal return and Q1 estimated tax
- June 15 — Q2 estimated tax
- September 15 — Q3 estimated tax and extended business returns
- October 15 — Extended personal return
If you’d prefer someone else to track all of this — and make sure your books are ready on time for each deadline — that’s exactly what we do.
Let Us Handle Your Deadlines →
Related Reading
- How Much Does a Bookkeeper Cost for a Small Business in the US?
- QuickBooks vs Xero for US Small Businesses: Which Is Better in 2026?
- Our Tax Services →
- Our Payroll Services →
- Frequently Asked Questions →
Cloud Accountants LLC is a Colorado-registered remote bookkeeping and tax firm serving small businesses across the United States. Deadlines in this article are based on federal IRS schedules for 2026. State deadlines vary — consult your state’s department of revenue for state-specific requirements.
