Missed the September estimated-tax payment? What to review now
The September 15 payment date has passed. Check what you paid, address any shortfall, and prepare your records for the next regular payment date.
Key takeaways
September 15 has passed; the next regular estimated-tax installment for calendar-year individuals is January 15, 2027.
Estimated payments can cover both income tax and self-employment tax when withholding is not enough.
Recalculate when income changes and keep confirmation of every payment instead of relying on a rough quarterly guess.
Check the missed payment before planning the next one
As of September 21, the regular September 15 estimated-tax installment is past due. Review your IRS payment confirmations before making another payment. The next regular installment is January 15, 2027, but waiting until then does not erase an earlier shortfall. Special rules or applicable disaster relief may change your situation.
A due date is not a reason to send the same amount automatically. If work slowed down, increased, or started during the year, use the current 2026 worksheet or ask a preparer whether the annualized-income method may apply.
Build the estimate from current records
Start with year-to-date business income, ordinary expense records, prior estimated payments, and any tax already withheld from another job. Publication 505 explains that federal tax is pay-as-you-go and that self-employed people generally use estimated payments when withholding does not cover the tax.
Separate business and personal spending, reconcile payment apps and bank deposits, and total mileage or other records while they are still fresh. The goal is a supportable estimate, not a perfect shoebox of receipts on the due date.
- Year-to-date invoices, deposits, and payment-app reports.
- Categorized expense receipts and mileage records.
- Prior 2026 estimated-payment confirmations and any W-2 withholding.
- Your 2025 return and the current 2026 Form 1040-ES worksheet.
Pay under the correct tax year and save proof
Form 1040-ES is used to figure and pay individual estimated tax. When paying electronically, confirm that the payment type and tax year are correct; when using a preparer, ask what amount was calculated and why.
Save the confirmation with your 2026 tax folder. If the amount is late, missing, or uncertain, address it promptly rather than waiting for filing season, because the IRS says an underpayment penalty can apply even when a refund is due later.
Common questions
Should I wait until January if I missed September’s payment?
Review the shortfall promptly. The IRS may assess an underpayment penalty for a late or insufficient installment even if a later payment covers the annual total. Ask a preparer to check your payment history and any applicable exceptions.
Do estimated payments include self-employment tax?
They can. IRS Publication 505 explains that estimated tax is used for income tax and other taxes, including self-employment tax.
