Stay compliant, avoid penalties, and keep cash flow predictable—without living in your accounting software.
Between client work, payroll, vendor payments, and growth goals, tax deadlines can feel like they show up “all at once.” The truth is that most tax stress comes from missing a few key dates—and from not knowing which deadlines apply to your business structure. This guide breaks down the most important upcoming tax return deadlines for 2026 (covering 2025 tax returns and 2026 estimated payments), with a practical checklist and a quick-reference table you can bookmark.
Why tax deadlines sneak up on business owners
For many small and mid-sized businesses, deadlines don’t feel “annual”—they’re monthly, quarterly, and event-driven. A few common reasons businesses get caught off guard:
• Your entity type changes the main return deadline (sole proprietor vs. partnership vs. S-corp vs. C-corp).
• Payroll filings run on a different cadence than income tax returns.
• Estimated tax payments are not evenly spaced—and “quarterly” doesn’t mean every three months.
• Extensions extend filing time, not the time to pay (in most cases).
If you’re building a business in Murrells Inlet (or anywhere along the Grand Strand), the most helpful approach is a simple deadline system: a calendar + a short monthly bookkeeping routine + proactive tax planning.
The “big three” deadlines most small businesses should track
If you track nothing else, track these:
1) March 16, 2026 (Monday)
Common deadline for many pass-through business returns: S-Corps (Form 1120-S) and Partnerships (Form 1065). If you’re waiting on clean books or K-1 details, this is often where an extension comes into play—but planning ahead keeps it smooth.
2) April 15, 2026 (Wednesday)
The main federal filing and payment deadline for individual returns (Form 1040), and commonly for some business returns as well. It’s also the due date for the first 2026 estimated tax payment for individuals.
October 15, 2026 (Thursday)
A major extension deadline for many individual returns (when a proper extension was filed). Extensions reduce “rush” risk, but they don’t replace year-round bookkeeping and tax planning.
Quick-reference table: important upcoming deadlines (2026)
Dates below reflect common federal deadlines. If you’re in a federally declared disaster area, some deadlines can shift—so it’s smart to confirm with a CPA before you assume a date applies.
| Deadline (2026) | Who it affects | What’s typically due | Practical note |
|---|---|---|---|
| Jan 26, 2026 | Individual filers | IRS begins accepting 2025 returns | Early filing works best when bookkeeping and 1099/W-2s are accurate. |
| Mar 16, 2026 | S-Corps & Partnerships | Form 1120-S / 1065 (or extensions) | Have your books closed before March so K-1s aren’t delayed. |
| Apr 15, 2026 | Most individuals + many businesses | Form 1040 deadline; extensions; payments due | If you extend, plan a payment to reduce underpayment risk. |
| Apr 15, 2026 | Estimated tax payers | 2026 Estimated Tax Payment #1 | Critical for owners with pass-through income or 1099 income. |
| Jun 15, 2026 | Estimated tax payers | 2026 Estimated Tax Payment #2 | Not spaced evenly—build it into cash flow forecasts. |
| Sep 15, 2026 | Estimated tax payers | 2026 Estimated Tax Payment #3 | Mid-year bookkeeping quality shows up here—clean books reduce guesswork. |
| Oct 15, 2026 | Individuals on extension | Extended 2025 Form 1040 deadline | Great time for year-end tax planning to avoid surprises. |
| Jan 15, 2027 | Estimated tax payers | 2026 Estimated Tax Payment #4 | Close the year strong—your Q4 results impact payment sizing. |
Note: South Carolina’s individual filing deadline is April 15, 2026; the SCDOR also indicates that filing and paying electronically by May 1, 2026 may help avoid penalties/interest in certain situations. Confirm your specific facts before relying on this as a “free extension.” (dor.sc.gov)
Step-by-step: how to stay ahead (without spending weekends “in QuickBooks”)
Step 1: Assign your entity type to the right deadline
If you’re an S-Corp or partnership, March is a real deadline—not an “optional early date.” If you’re a sole proprietor, your business activity flows to your individual return (often April).
Step 2: Close your books monthly (lightweight, consistent)
A monthly close doesn’t need to be complicated. Focus on:
• Reconcile bank and credit card accounts
• Categorize transactions consistently
• Review A/R and A/P for timing and cash flow
• Save receipts and document “why” for unusual expenses
If you want financial reports you can trust (not just a tax file), accurate bookkeeping is the foundation. For ongoing support, explore JTC CPAs bookkeeping services.
Step 3: Forecast taxes the same way you forecast payroll
Owners in service businesses often experience “profit whiplash” (a big month followed by a slow month). Estimated tax dates—April 15, June 15, and September 15—are fixed, even if your revenue isn’t. Using a rolling forecast and setting aside a percentage of owner draws can reduce surprises. The IRS confirms the standard estimated payment due dates by payment period. (irs.gov)
Step 4: Use extensions strategically (not as a default)
Extensions can be a smart tool when you’re waiting on final K-1s, corrected 1099s, or need time to finalize books. But many taxpayers learn too late that an extension is typically an extension to file, not an extension to pay. If you extend, plan a reasonable payment alongside the extension.
For proactive strategy (rather than last-minute filing), consider year-round guidance through tax planning services and streamlined tax return preparation.
Did you know? Quick facts that prevent expensive mistakes
The 2026 filing season opened January 26, 2026. That’s when the IRS began accepting 2025 individual returns. (irs.gov)
“Quarterly” estimated taxes aren’t evenly spaced. Payment #2 is due June 15, not July 15—so your cash plan needs to match the actual calendar. (irs.gov)
BOI reporting changed. FinCEN indicates U.S.-created entities are now exempt from BOI reporting under an interim final rule (with new deadlines focused on certain foreign entities). If you operate across borders, confirm whether you’re affected. (fincen.gov)
Local angle: what Murrells Inlet business owners should plan for
Murrells Inlet and the surrounding coastal communities often see seasonal demand shifts (tourism, hospitality, real estate activity, and service providers supporting those industries). That seasonality can make estimated taxes and payroll planning tricky—because your “best months” and your “tax due months” don’t always align.
A practical local playbook:
• Run a spring forecast (March/April) to anticipate the April 15 payment and filing rush.
• Review staffing and contractor spend ahead of summer to reduce payroll surprises.
• Schedule a late-summer tax check-in so September 15 isn’t a scramble.
Even if your CPA team is based in Boise, having a proactive, systems-driven process matters more than geography—especially if your business is scaling or adding complexity (payroll, multiple states, new entities, or future sale plans).
CTA: Put deadlines on autopilot with a proactive CPA team
If you want a clear tax calendar, clean books, and a plan for estimated payments—without spending weekends sorting transactions—JTC CPAs can help you build a repeatable process.
FAQ: important upcoming tax return deadlines
What is the federal deadline to file 2025 individual taxes?
For most taxpayers, the deadline is April 15, 2026. (irs.gov)
When are 2026 estimated tax payments due?
For most individuals who need to pay estimated taxes, the IRS lists due dates by payment period: April 15, 2026, June 15, 2026, September 15, 2026, and January 15, 2027. (irs.gov)
If I file an extension, do I get more time to pay?
An extension usually gives more time to file paperwork, but not more time to pay what you owe. Many taxpayers choose to send an estimated payment with the extension to reduce penalties/interest risk.
I’m behind—should I ignore it until tax time?
Waiting usually makes it more expensive and more stressful. If you’re dealing with unfiled returns or back taxes, consider addressing it early with professional support. JTC CPAs offers tax resolution services designed to move things forward step-by-step.
How do I know which deadlines apply to my business?
Your entity type (sole proprietor, partnership, S-corp, C-corp), payroll setup, and whether you have contractors all affect deadlines. A CPA can map your compliance calendar and align it with bookkeeping and tax planning so it’s manageable.
Glossary
Estimated Taxes
Payments made during the year (often by business owners and self-employed individuals) to cover income tax and self-employment tax when withholding isn’t enough.
Pass-Through Entity
A business structure where profits “pass through” to the owner’s personal return (commonly partnerships and S-corporations), often creating the need for estimated tax payments.
K-1
A tax form that reports an owner’s share of income, deductions, and credits from a partnership or S-corporation—commonly needed before an owner can finalize their personal return.
Tax Extension
A request for extra time to file certain tax returns. It typically does not eliminate interest or penalties if you pay late; planning an extension payment is often wise.
