Missed the September 15 Tax Deadline? What to Do Next
September 15 was an important federal tax deadline for many individuals and businesses. If the date slipped past you, the most important thing is not to ignore it.
The deadline applied to several tax obligations, including third-quarter estimated tax payments for certain taxpayers and extended returns for many calendar-year partnerships and S corporations.
What Was Due on September 15?
Depending on your situation, the September 15 deadline may have included:
Third-quarter estimated tax payments for individuals who are required to make quarterly payments
Estimated tax installments for certain corporations
Extended calendar-year partnership returns filed on Form 1065
Extended calendar-year S corporation returns filed on Form 1120-S
Other filing or payment requirements depending on the taxpayer or entity
If you are unsure whether the deadline applied to you or your business, reviewing your tax records with a tax professional can help identify any outstanding obligations.
What Happens If You Missed an Estimated Tax Payment?
The federal tax system generally requires taxpayers to pay taxes throughout the year through withholding, estimated tax payments, or a combination of both.
If you did not pay enough tax by an applicable estimated tax deadline, an underpayment penalty may apply.
Rather than waiting until the next quarterly deadline, it may be helpful to review your current income, payments already made, and projected tax liability for the rest of the year.
Making adjustments now may help you better prepare for upcoming tax obligations.
What If You Missed an Extended Business Return?
It is important to remember that an extension to file generally gives you more time to submit a return, but it does not necessarily extend the time to pay taxes that were already due.
If your partnership, S corporation, or another entity missed its extended filing deadline, the next step depends on the type of return and your specific circumstances.
The longer an outstanding filing remains unresolved, the more complicated the situation may become.
Gather your tax documents and speak with your tax professional as soon as possible to determine the appropriate next steps.
What Should You Do Now?
Start by identifying exactly what was missed.
Was it an estimated tax payment? An extended business return? Or both?
Next, gather records showing:
Estimated tax payments already made
Current-year income
Business income and expenses
Payroll and withholding information
Major financial changes during the year
Relevant prior-year tax documents
Having this information ready can make it easier for your tax professional to evaluate your situation.
Do Not Simply Wait Until the Next Deadline
For many individuals making estimated payments, the next general estimated tax payment deadline is January 15, 2027.
However, that does not necessarily mean a missed September payment should simply be postponed until January.
Your tax situation may have changed during the year, particularly if your income increased, your business grew, you added a new source of revenue, or you completed a major financial transaction.
Reviewing your numbers before year-end can help identify whether your estimated payments still reflect your expected tax liability.
A Missed Deadline Can Be a Tax Planning Opportunity
Missing a deadline can also be a sign that your current tax planning process needs attention.
Maybe your estimated payments have not kept pace with your income. Perhaps your business has grown significantly, you added another revenue stream, or your financial situation changed during the year.
Instead of waiting until tax season to discover a problem, consider reviewing your tax position before year-end.
Proactive planning can help you understand what may still be due and prepare for upcoming filing and payment deadlines.
Need Help Reviewing Your Tax Situation?
If you missed the September 15 deadline or are unsure whether you have outstanding tax obligations, Virtual CPAs can help you review your situation and determine your next steps.
This article is provided for general educational purposes only and should not be considered individualized tax, legal, or financial advice. Tax requirements vary based on each taxpayer’s circumstances.