Third 2026 installment

Q3 Estimated Tax Payment 2026

The payment is due September 15, 2026 and generally covers income from june 1 through august 31, 2026.

Income period

June 1 through August 31, 2026

Due date

September 15, 2026

Federal form

Form 1040-ES

Payment checklist

1. Reforecast annual income. Include self-employment profit, investment income, retirement distributions and wages.
2. Test the safe harbor. Compare 90% of current-year tax with 100% or 110% of prior-year tax, subject to the IRS rules.
3. Subtract withholding and prior installments. Withholding is generally treated as paid evenly through the year for penalty calculations.
4. Pay and save proof. Use an IRS electronic payment method or the Form 1040-ES voucher and retain confirmation.

The existing planner calculates annual tax, safe harbor, prior payments and the net amount due by quarter.

Four installments (4/15, 6/15, 9/15, 1/15), safe harbor 90%/100%

Form 2210 safe harbor, 90%/100% prior-year test, 7% rate

Form 1040-ES Q1 through Q4 payment dates, covered income periods, and quarter-specific planning guides