The short version
The IRS encourages taxpayers to file as soon as their information is complete instead of waiting until the final days before the deadline. Filing early gives you more time to resolve missing documents, address unexpected tax issues, and understand any remaining balance before October 15. Here is what extended filers need to know—and why the September 15 estimated-tax deadline may also require your attention.
An Extension to File Was Not an Extension to Pay
A federal tax extension provides additional time to submit your return. It does not provide additional time to pay the tax you owe.
For most individual taxpayers, any 2025 federal income tax balance was due April 15, 2026. If you did not pay the full amount by that date, interest and potentially penalties may continue to accrue—even if your extension was filed properly.
Filing your return sooner can help determine the exact balance and prevent the failure-to-file penalty from becoming an additional problem after October 15.
If you cannot pay the entire balance, you should generally still file the return on time and consider available IRS payment options. Waiting to file because you cannot pay may make the situation more expensive.
Why You Should Not Wait Until October 15
Waiting until the deadline can create unnecessary risks, especially if your return includes:
- Business or self-employment income
- Multiple states
- Rental properties
- Foreign income or financial accounts
- Stock options, RSUs, cryptocurrency, or investment activity
- Late or corrected tax documents
- Partnership, S corporation, trust, or estate reporting
- Significant changes in income or deductions
These returns may require additional documents, calculations, disclosures, or coordination with other tax professionals.
Submitting your information early also leaves time to identify missing Forms K-1, brokerage statements, foreign account details, bookkeeping corrections, or inconsistencies with information already reported to the IRS.
Do Not Forget the September 15 Estimated-Tax Deadline
Extended filers may be managing two separate tax obligations this fall.
The third estimated-tax payment for the 2026 tax year is due September 15, 2026. This payment may apply to taxpayers who earn income that is not adequately covered by withholding, including:
- Business owners and independent contractors
- Partners and S corporation shareholders
- Landlords
- Investors
- Retirees receiving taxable distributions
- Taxpayers with substantial interest, dividend, or capital-gain income
- Individuals with foreign or other non-wage income
The September payment is for your expected 2026 tax liability. It is separate from any balance associated with the extended 2025 return due October 15.
According to the 2026 IRS estimated-tax schedule, the remaining individual estimated-tax deadlines are September 15, 2026, and January 15, 2027.
If your income has changed significantly during the year, relying on last year’s payment amount may not be sufficient. A new projection can help determine whether your estimated payments or payroll withholding should be adjusted.
What Extended Filers Should Do Now
Before the October deadline, confirm that your tax professional has received all relevant information, including:
- Wage and income statements
- Business income and expense records
- Forms K-1
- Brokerage and cryptocurrency reports
- Rental-property activity
- Estimated-tax payment confirmations
- Foreign income and account information
- Charitable contribution records
- Retirement contributions and distributions
- Any corrected or recently received tax forms
You should also verify how much you paid with your extension and through subsequent estimated-tax payments. Payment records are frequently missing from tax organizers, which can cause an incorrect balance or refund calculation.
Some Taxpayers May Have Additional Time
October 15 is the deadline for most individual taxpayers who received an extension, but exceptions may apply to certain military personnel, taxpayers serving in combat zones, and people affected by federally declared disasters.
Do not assume an exception applies without confirming your eligibility and the applicable relief period.
Get Your Return and Tax Projection Reviewed Now
The weeks before October 15 are an opportunity to do more than complete last year’s return. They are also an important time to review your 2026 income, estimated payments, withholding, and year-end planning opportunities.
Valoria Consulting assists individuals and business owners with extended tax returns, complex reporting, estimated-tax calculations, and proactive tax planning.
If your 2025 return is still incomplete—or you are unsure whether your September 15 estimated payment is sufficient—contact us now to schedule a consultation. Waiting until the final deadline may limit the time available to resolve complex issues and identify planning opportunities.
Related reading
- What Are My Options If I Owe the IRS?
- 5 Tax Mistakes That Could Cost You Thousands
- Ten Signs You're Paying More Taxes Than You Need To
- What Business Owners Should Do After Receiving an IRS Notice
This article is for general informational purposes and does not constitute tax, accounting, or legal advice. Filing deadlines, estimated-tax requirements, and available relief depend on each taxpayer's individual circumstances.
Beat the October 15 Deadline
Schedule a consultation with Valoria Consulting to complete your extended 2025 return, review your September 15 estimated payment, and get ahead of year-end planning.