The third-quarter estimated tax payment for 2026 is due Tuesday, September 15, 2026. You generally must pay if you expect to owe $1,000 or more when you file your 2026 return and your income is not covered by withholding — the classic cases being self-employment, gig and freelance work, rental income, and significant investment gains.
Q3 covers income earned June 1 through August 31. Miss the date and the IRS charges an underpayment penalty that works like interest — and paying extra later does not erase a quarter you shorted.
Who actually has to make the September 15 payment?
Ask two questions:
- Will you owe $1,000+ at filing time after subtracting withholding and refundable credits?
- Will your withholding fall short of the safe harbor (90% of this year’s tax, or 100%/110% of last year’s)?
If both answers are yes, you owe estimated payments. Typical profiles: freelancers and independent contractors, small business owners, landlords, retirees with large IRA withdrawals and no withholding, and investors who realized big gains this summer. W-2 employees with a side income often can skip separate payments by raising paycheck withholding instead — withholding is treated as paid evenly through the year, a legal quirk that can retroactively fix earlier quarters.
How much should you pay to avoid a penalty?
Aim for a safe harbor — whichever is smaller:
| Safe harbor | Rule |
|---|---|
| Current-year | Pay at least 90% of your actual 2026 tax, spread across the four due dates |
| Prior-year | Pay 100% of your 2025 total tax — 110% if your 2025 AGI was over $150,000 |
The prior-year harbor is the stress-free option: the number is fixed and known. Take your 2025 total tax (line 24 of your 1040, roughly), multiply by 1.0 or 1.1, divide by four, and pay that each quarter regardless of how 2026 is actually going. If your income collapsed this year, the 90%-of-actual route saves cash — or the annualized income method lets uneven earners match payments to when income actually arrived.
What happens if you miss or short the payment?
The underpayment penalty accrues like interest on the shortfall, at the federal rate set quarterly, from the due date until paid. Key facts:
- Each quarter stands alone. Overpaying Q4 does not cure a missed Q3.
- It is not a criminal or flat penalty — it is functionally interest, so paying even a few weeks late costs relatively little. Pay as soon as you notice, do not wait for the next due date.
- Form 2210 computes the penalty at filing; the IRS will also happily compute it for you and send a bill.
If you end up owing more at filing time than you can pay, that is a separate problem with its own tools — see IRS payment plans in 2026.
How do you actually pay?
Fastest to slowest:
- IRS Online Account — pay from a bank account and see your payment history in one place (the history view is the best defense against "did I pay Q2?" doubts).
- IRS Direct Pay — no login needed; choose "Estimated Tax" and tax year 2026.
- EFTPS — the Treasury’s system, best for businesses and scheduled payments.
- Check with Form 1040-ES voucher — postmark by September 15.
Label the payment correctly (estimated tax, 2026). Misapplied payments are fixable but tedious.
Do unemployment or benefit payments require estimated taxes?
Sometimes. Unemployment benefits are federally taxable, and states do not always withhold — a long stretch on benefits can generate a surprise bill, as explained in how the 1099-G works. Social Security is different: at most 85% of it is taxable and many recipients owe nothing, but retirees with substantial other income sometimes make estimated payments or file Form W-4V to add withholding instead.
FAQ
Q. What are the remaining due dates for 2026 taxes?
A. September 15, 2026 (Q3) and January 15, 2027 (Q4). The Q4 payment is skippable if you file your full return and pay by February 1, 2027.
Q. I missed June’s Q2 payment. Should I double up on September 15?
A. Pay the missed amount immediately rather than waiting — the penalty accrues daily. Then make Q3 on time.
Q. Do I need to file a form with each payment?
A. No form is filed with electronic payments. Form 1040-ES is only a worksheet plus mail-in vouchers.
Q. Do states have the same September 15 deadline?
A. Most states with income taxes mirror the federal dates, but a few differ (California notably front-loads payments). Check your state revenue site.
Source: IRS – Estimated Taxes