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Key Tax Deadlines in September 2025 for Individuals

As the autumn months approach, it's crucial to stay on top of important tax deadlines that can impact your financial health and planning for the future. September 2025 brings specific due dates that individuals must keep in mind, particularly in the realms of tip reporting and estimated tax payments. This article will guide you through essential tax preparation steps, safe harbor rules, and strategies to navigate potential penalties as you prepare for the upcoming tax year.

Strategic Considerations for Fall 2025 and Beyond

To successfully manage your tax obligations, consider scheduling a consultation with our office to discuss tailored tax planning strategies.

September 10 - Mandatory Tip Reporting

If you earn tips as part of your compensation and these exceed $20 in August, you must report them to your employer using IRS Form 4070 by September 10. Your employer is then responsible for deducting FICA taxes and any necessary income tax withholding from your regular pay. In instances where your wages aren't sufficient to cover the required withholdings, your employer will indicate the uncollected amounts in box 8 of your W-2. These amounts will need to be settled when filing your annual tax return.
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September 15 - Estimated Tax Payments Due

Mid-September marks the deadline for the third installment of estimated taxes for individuals in 2025. The IRS mandates a "pay-as-you-earn" tax system, which can be met through payroll withholding for employees, pension withholding for retirees, and quarterly estimated tax payments for those with supplemental income not covered by withholding.

Failing to meet a safe harbor (minimum) prepayment can result in underpayment penalties, calculated at the federal short-term rate plus three percentage points, assessed quarterly. Federal law offers methods to avoid these penalties. If the underpayment is less than $1,000, no penalty applies. Additionally, there are two key safe harbor prepayments:

  • If your current year's tax payments cover at least 90% of what you owe, you may avoid penalties.
  • Paying 100% of your previous year’s tax liability generally qualifies as a safe harbor (increasing to 110% for individuals with an AGI over $150,000 or $75,000 if married filing separately).

Example: If your yearly tax is $10,000 and prepayments are $5,600, leaving an additional $4,400 due, you must check safe harbor eligibility. If prior year's liability was $5,000 and prepayments exceed 110% of this figure, as in this case ($5,600 > $5,500), you're safe from penalties, illustrating the importance of strategic prepayments, especially with sudden income spikes from stock sales or bonuses.

For varying state de minimis amounts and safe harbors, consult with our office for specific rules.
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Extended Deadlines for Weekends, Holidays, and Disasters

Due dates that fall on weekends or holidays are automatically extended to the next business day. Additionally, extensions are granted to those in federally declared disaster zones. For current disaster area designsations or extensions, visit the following sites:
FEMA: FEMA Disaster Declarations
IRS: IRS Tax Relief in Disaster Situations

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