September 2026 Tax Deadlines: Tip Reporting and Estimated Taxes

Fall is an ideal time to assess your 2026 tax situation and begin planning for 2027. With an estimated tax payment approaching this month, it is a great opportunity to review your current income, withholdings, and prepayments to determine if year-end adjustments are necessary. If you need assistance evaluating your strategy, contact our office to schedule a tax planning consultation.

September 10: Reporting Tip Income

Employees who work for tips and accumulated more than $20 during August must report this income to their employer no later than September 10. You can fulfill this requirement using IRS Form 4070 or a custom written statement. A custom statement must include your signature; your name, address, and Social Security number; your employer's name and address (or the establishment's name); the specific period covered; and the total tips received during that time.

Your employer is legally required to withhold FICA and income taxes on these tips from your regular wages. If your standard wages fall short of covering these taxes, the employer will report the uncollected withholding amount in box 8 of your W-2. You will then be responsible for paying this uncollected withholding when you file your annual tax return.

September 15: Third Quarter Estimated Tax Payments

Tax professional planning estimated payments

The third installment for 2026 individual estimated taxes is due on September 15. The federal tax system operates on a pay-as-you-earn basis, and the government provides several methods to help taxpayers meet this standard:

  • Payroll withholding for employees;
  • Pension withholding for retirees; and
  • Estimated tax payments for self-employed individuals and those with other sources of income not covered by withholding.

Avoiding the Underpayment Penalty

Failing to prepay a minimum required amount—known as a safe harbor—can trigger an underpayment penalty. Calculated quarter-by-quarter, this penalty equals the federal short-term rate plus 3 percentage points.

Federal tax law provides exemptions to help taxpayers avoid this penalty. No penalty is assessed if your underpayment is less than $1,000 (the de minimis amount). Additionally, there are two primary safe harbor prepayments:

  • Current Year Safe Harbor: You can escape a penalty if your prepayments equal or exceed 90% of the tax owed in the current year.
  • Prior Year Safe Harbor: You can avoid a penalty if your payments equal 100% of the preceding year's tax liability. However, for taxpayers with an Adjusted Gross Income (AGI) over $150,000 ($75,000 for married individuals filing separately), this safe harbor requirement increases to 110% of the prior year's tax.

A Practical Safe Harbor Example

Suppose your tax liability for the year is $10,000 and your prepayments total $5,600. The result is that you owe an additional $4,400 on your tax return. To find out if you owe a penalty, see if you meet the current year exception. Since 90% of $10,000 is $9,000, your $5,600 prepayments fall short, meaning you cannot avoid the penalty under the first safe harbor.

However, the second safe harbor may still apply. Assume your prior year's tax was $5,000. Because your $5,600 prepayment is greater than 110% of the prior year's tax ($5,500), you successfully qualify for this safe harbor and can escape the penalty.

This example highlights why tracking adequate prepayments is essential, particularly if you experience a large increase in income from the sale of stocks or property, large bonuses, or retirement. Timely payment of each required estimated tax installment is mandatory to qualify for the safe harbor exception. Contact our office promptly if you have questions regarding your estimates.

State Tax Rules and Differences

CAUTION: Some state de minimis amounts, safe harbor estimate rules, and estimated payment due dates differ from federal guidelines. Please call our office to discuss the specific safe harbor rules in your state.

Weekends, Holidays, and Disaster Area Extensions

When a standard tax deadline falls on a Saturday, Sunday, or legal holiday, the due date is automatically extended until the next business day that is not a legal holiday.

Additionally, deadlines are extended for taxpayers located in designated geographical disaster areas. For more information on whether an area has been designated a disaster area and to view adjusted filing extension dates, visit the following websites:

FEMA: https://www.fema.gov/disaster/declarations
IRS: https://www.irs.gov/newsroom/tax-relief-in-disaster-situations

Finalize Your Fall Tax Strategy

Staying ahead of September due dates keeps you in compliance and protects you from unnecessary underpayment penalties. Reach out to schedule a tax planning consultation so we can help keep your strategy on track before the year ends.

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