Key Tax Deadlines for September 2025: Plan Ahead

As September 2025 approaches, it's crucial for individuals to be alert to key tax deadlines, including tip reporting and estimated tax payments. Ensuring compliance with tax requirements, understanding safe harbor rules, and strategizing for 2026 can help you avoid penalties and optimize tax planning.

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September 10 - Tip Income Reporting

Employees receiving tips over $20 in August must report these to their employer via IRS Form 4070 by September 10. Employers are required to deduct FICA and income tax from these tips. If regular wages don't cover the withholding, the uncollected amount will be noted in box 8 of your W-2 and will need to be settled upon filing your annual return.

September 15 - Estimated Tax Payment Due

The third installment for 2025 individual estimated taxes is due. Our tax framework operates as a “pay-as-you-earn” model, accommodating taxpayers with multiple prepayment options:

  • Payroll withholding for employees;

  • Pension withholding for retirees;

  • Estimated tax payments for those with non-withholding income sources, such as self-employment.

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Failure to meet the safe harbor (minimum) prepayment can result in an underpayment penalty. This is calculated quarterly at the federal short-term rate plus 3%.

To avoid potential penalties, consider:

  • The de minimis exception, where underpayments below $1,000 incur no penalty;

  • Utilizing “safe harbor” prepayments:

    • If current year payments cover at least 90% of owed taxes, no penalty applies;
    • Alternatively, payments equaling 100% of the previous year's taxes (110% for those with an AGI above $150,000, or $75,000 if filing separately) can also exempt you from penalties.

Example Case: If your taxes amount to $10,000 but you've prepaid only $5,600, you'll owe $4,400. The first safe harbor requires prepayments of $9,000 (or 90% of $10,000), rendering you liable for a penalty. However, if last year’s taxes were $5,000, your prepayment of $5,600 surpasses the 110% threshold ($5,500), ensuring penalty exemption.

This highlights the importance of accurate prepayments, especially with potential income surges from bonuses, asset sales, or retirement. Timely estimated payments are also needed to leverage the safe harbor exceptions.

For detailed guidance on safe harbor estimates, please contact our office promptly.

State Specifics and Caution: Be aware that some state de minimis and safe harbor rules differ from federal standards. Contact us for guidance on state-specific rules.

Image 2Adjustments for Weekends & Holidays

If your due date lands on a weekend or holiday, it extends to the next business day.

Disaster Area Extensions
In designated disaster zones, filing dates are extended. Verify regional disaster statuses and new deadlines at:
FEMA: https://www.fema.gov/disaster/declarations
IRS: https://www.irs.gov/newsroom/tax-relief-in-disaster-situations

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