The third 2026 estimated tax payment deadline is September 15 for calendar-year taxpayers. That date applies to federal estimated tax payments and to New York personal income tax estimated payments. For many self-employed professionals, partners, S corporation shareholders, and small-business owners, this payment is an important part of staying current and avoiding an unexpected balance or underpayment penalty.
Estimated taxes are not limited to federal income tax. Depending on your situation, they may also cover self-employment tax and other liabilities that are not fully paid through withholding.
Who may need to make an estimated payment?
Individuals—including sole proprietors, partners, and S corporation shareholders—generally need to make estimated payments when they expect to owe at least $1,000 after subtracting withholding and refundable credits. Corporations generally use a $500 threshold. The correct calculation depends on the taxpayer’s income, entity type, withholding, credits, prior-year return, and any significant changes during 2026.
Common situations that can create an estimated tax obligation include:
- Self-employment or freelance income
- Partnership or S corporation income
- Rental or investment income
- Capital gains
- Insufficient withholding from wages or retirement income
- A substantial increase in income during the year
Five items to review before September 15
1. Year-to-date income
Do not automatically reuse last year’s quarterly payment when this year’s income is materially different. Review revenue, wages, investment activity, rental income, and other taxable income received through August.
2. Business expenses and bookkeeping
Up-to-date records make the estimate more reliable. Reconcile bank and credit-card accounts and identify deductible business expenses before calculating the payment.
3. Federal and New York payments already made
Confirm prior estimated payments and withholding. Review both IRS and New York records when applicable. A missed or incorrectly applied payment can materially change the remaining amount due.
4. Changes in your business or household
A new business, change of entity, property sale, retirement distribution, new dependent, or change in filing status may affect the calculation.
5. The payment method and confirmation
The IRS offers electronic payment options through an IRS Online Account and other approved methods. Keep the confirmation with your tax records. Business payment methods may differ depending on the entity and type of tax.
What if the September 15 deadline is missed?
Paying late can result in an underpayment penalty, even when a taxpayer later receives a refund. The appropriate next step depends on how much should have been paid, when the income was earned, and whether an exception or annualized-income calculation applies. Paying promptly and recalculating the remaining year is generally better than ignoring the missed installment.
Local year-round tax planning
Quarterly payments work best as part of an ongoing tax plan rather than a last-minute calculation. Go Tax Dude serves Port Washington and nearby Nassau County individuals and small businesses with tax preparation, tax planning, small-business accounting, bookkeeping, payroll accounting, and IRS representation. Our CPA and Enrolled Agent team brings more than 15 years of professional tax and accounting experience.
If your income changed or you are unsure whether your September payment is sufficient, schedule a tax consultation before submitting a number based only on last year’s estimate.
Disclaimer: This article provides general educational information and is not individualized tax advice. Tax rules and calculations depend on each taxpayer’s facts and circumstances.