Key September 2025 Tax Deadlines and Smart Planning Strategies

September 2025 Tax Deadlines bring important obligations such as tip reporting and estimated tax payments to the forefront. Master safe harbor rules, avoid penalties, and prepare effectively for 2026.

2025 Fall and 2026 Tax Planning

Schedule a consultation with our office to optimize your tax planning strategies. Ensuring preparedness is crucial to minimizing obligations and maximizing tax efficiencies.

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September 10 - Report Tips to Employer

If you are a tipped employee and earned more than $20 in tips during August, report them to your employer using IRS Form 4070 by September 10. Employers must withhold FICA taxes and income tax from these tips. Should your wages be insufficient to cover these withholdings, the employer must report the uncollected amount on your W-2 in box 8. You'll need to pay this when filing your tax return.

September 15 - Estimated Tax Payment Due

The third installment of 2025 individual estimated taxes is due. Our "pay-as-you-earn" tax system offers methods to help taxpayers meet their obligations, including:

  • Payroll withholding for employees;

  • Pension withholding for retirees;

  • Estimated tax payments for the self-employed and others with non-withholding income.

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To avoid underpayment penalties, which are calculated as the federal short-term rate plus three percentage points on a quarterly basis, consider federal tax law's safe harbor prepayments:

  • Prepay at least 90% of your current year's tax to qualify for the first safe harbor and avoid penalties.

  • The second safe harbor involves paying 100% of the prior year's tax. For those with an AGI over $150,000 (or $75,000 for married filing separately), this increases to 110%.

Example: If 2025 taxes total $10,000 and prepayments reach $5,600, a $4,400 gap exists. The 90% rule (safe harbor one) means you fall short. However, if 2024 taxes were $5,000 and you prepaid $5,600, this exceeds the 110% requirement of the prior year, qualifying you for the safe harbor.

This highlights why ensuring adequate prepayments is crucial, especially if income surges from selling assets, receiving bonuses, or changes like retirement. Making timely estimated tax prepayments is also essential. For questions about estimates, contact us promptly.

CAUTION: State-specific safe harbors differ from federal ones. Consult us for accurate state rules.

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Weekend & Holiday Extensions: If deadlines occur on weekends or holidays, they extend to the next business day.

Disaster Area Extensions: Declared disaster zones have extended due dates. Check FEMA and IRS sites for updates on affected areas and extensions:

FEMA: fema.gov/disaster/declarations

IRS: irs.gov/newsroom/tax-relief-in-disaster-situations

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