September 15 Estimated Tax Deadline 2026: What to Do
September 15, 2026, is the third estimated tax payment deadline for calendar-year individuals. If you expect to owe enough federal tax after withholding and refundable credits, you may need to make a 2026 Form 1040-ES payment by that date. Employees with wages may instead increase federal withholding, or combine additional withholding with a direct payment.
The right move depends on your full-year tax estimate, what has already been withheld, and what you paid in April and June. This guide gives you a practical way to check those numbers before choosing an option.
For most calendar-year taxpayers, the Q3 estimated tax payment is due September 15, 2026. Estimate your annual required payment, subtract projected withholding, then compare the cumulative amount required through September with payments already made. Pay the shortfall, increase W-4 withholding, or use both after checking how many paychecks remain.
This article covers federal individual estimated tax. State and local schedules, thresholds, payment systems, and disaster postponements can differ. Confirm the current rules with your state tax agency and check IRS disaster-relief announcements before relying on September 15.
When Is the September Estimated Tax Deadline in 2026?
The third payment for tax year 2026 is due Tuesday, September 15, 2026. It covers the June 1 through August 31 payment period under the IRS calendar. The IRS divides the year into payment periods rather than equal three-month quarters, which is why “Q3” is convenient shorthand but not the exact IRS description.
| Income payment period | 2026 estimated tax due date | Status as of September 3, 2026 |
|---|---|---|
| January 1–March 31 | April 15, 2026 | Passed |
| April 1–May 31 | June 15, 2026 | Passed |
| June 1–August 31 | September 15, 2026 | Upcoming |
| September 1–December 31 | January 15, 2027 | Future payment |
The official 2026 Form 1040-ES package says you do not have to make the January 15, 2027 payment if you file your 2026 return by February 1, 2027 and pay the entire balance due with the return. February 1 reflects the weekend adjustment shown on the current form.
Who May Need to Pay Estimated Tax by September 15?
Estimated tax is common when income does not have enough federal tax withheld. It can affect freelancers, sole proprietors, partners, S corporation shareholders, landlords, investors, retirees, and employees who also earn untaxed income.
Under the general 2026 rule, you usually need estimated payments only when both statements are true:
- You expect to owe at least $1,000 for 2026 after subtracting federal income-tax withholding and refundable credits.
- Your expected withholding and refundable credits are less than the smaller of 90% of your 2026 tax or 100% of the tax shown on your 2025 return, assuming the 2025 return covered 12 months.
This is a prepayment test, not a promise that your final return will show no balance. You can satisfy a penalty safe harbor and still owe more when you file.
Gig workers should use actual app statements, bank deposits, expense records, and bookkeeping totals when projecting business profit. The ePaystubs guide to documenting gig-work income explains how these records serve a different purpose from a pay stub.
What Is the 2026 Estimated Tax Safe Harbor?
A safe harbor is a federal prepayment threshold that can help you avoid an underpayment penalty. For many taxpayers, the required annual payment is the smaller of:
- 90% of the tax expected on the 2026 return; or
- 100% of the tax shown on the 2025 return.
If your 2025 adjusted gross income was more than $150,000—or more than $75,000 if your 2026 filing status is married filing separately—the prior-year percentage generally becomes 110%. Different rules apply to qualifying farmers and fishermen.
Assume your projected 2026 total tax is $16,000. Ninety percent is $14,400. Your 2025 total tax was $13,200, your 2025 return covered 12 months, and the higher-income 110% rule does not apply. The smaller figure is $13,200, so that is the example’s required annual payment before subtracting projected withholding.
Use the current Form 1040-ES worksheet rather than treating the example as your calculation. Total tax, refundable credits, self-employment tax, Additional Medicare Tax, household employment taxes, special deductions, and other items can change the result.
How to Calculate the Estimated Tax Amount Due September 15
Start with your required annual payment, not simply one-fourth of your expected year-end balance. Then subtract the federal withholding you reasonably expect for all of 2026. If your income arrives evenly and you use the regular installment method, compare 75% of the remaining annual estimated-tax requirement with what you already paid for April and June.
| Calculation step | Example amount | What it means |
|---|---|---|
| Required annual payment under safe-harbor test | $13,200 | Smaller of the applicable current-year and prior-year targets in this example. |
| Less expected 2026 federal withholding | − $4,800 | Includes federal income tax expected to be withheld during 2026. |
| Annual estimated-tax requirement | $8,400 | Amount remaining after the example’s projected withholding. |
| Cumulative target through September 15 | $6,300 | 75% of $8,400 using regular equal installments. |
| April and June payments already made | − $4,200 | Two payments of $2,100 each. |
| Example September payment | $2,100 | Brings cumulative estimated payments to $6,300. |
If the April or June installment was late or too small, paying more in September can reduce the unpaid balance going forward, but a penalty may still apply for the earlier period. Use Form 2210 instructions or consult a qualified tax professional when timing is material.
If your income was uneven—for example, you sold stock in August or your business became profitable in July—the annualized income installment method may produce a different payment. IRS Publication 505 explains that method, and the IRS specifically directs taxpayers with a large gain to the Annualized Estimated Tax Worksheet.
Should You Pay Form 1040-ES, Increase W-4 Withholding, or Do Both?
There is no universal best choice. A direct estimated payment addresses the amount immediately. Additional wage withholding spreads the catch-up over remaining paychecks. A combination can protect the deadline while making the rest easier to manage.
| Choice | May fit when | Main caution |
|---|---|---|
| Pay estimated tax now | You have the cash, no employer withholding, few paychecks left, or a clear September shortfall. | Choose the correct tax year and payment type. Keep the confirmation. |
| Increase W-4 withholding | You receive wages and can cover the projected shortfall through the remaining payrolls. | Your employer may not apply a replacement W-4 immediately, and excessive withholding reduces take-home pay. |
| Use both | You need to cover part of the September target now but want payroll withholding to handle the remaining projected obligation. | Coordinate both amounts so you do not accidentally pay twice. |
Why late-year withholding can be useful
For the installment calculation described in IRS Publication 505, one-fourth of expected federal withholding is considered withheld on each payment due date. That treatment can make additional late-year wage withholding useful when correcting a projected shortfall. Your exact penalty calculation can differ, especially if you elect to use actual withholding dates or the annualized method.
To request extra withholding from wages, enter an additional dollar amount per pay period in Form W-4, Step 4(c). Give the form to your employer, not the IRS. Under 2026 Publication 15, an employer receiving a replacement W-4 must generally begin using it no later than the first payroll period ending on or after the 30th day after receipt. Some employers may process it sooner.
Suppose your remaining projected federal shortfall is $3,600 and payroll confirms that six paychecks will use the updated W-4. Dividing $3,600 by six gives an example additional withholding amount of $600 per paycheck. If only five checks will use it, the same shortfall would require $720 per check. Recheck the number when income, deductions, credits, or payroll timing changes.
Review current and year-to-date federal withholding on your latest pay statement before doing the math. If the columns are unfamiliar, see how to read YTD earnings, taxes, and deductions and what FIT or FWT means on a pay stub.
Estimate income, deductions, credits, total tax, and federal withholding for all of 2026.
Compare the applicable current-year and prior-year payment targets.
Ask when payroll can apply a new W-4 and count only the affected paychecks.
Cover the September need with a payment, added withholding, or a coordinated mix.
Recalculate If Your Income Changed During 2026
A payment estimate made in April can be wrong by September. Recalculate when a large event changes income, deductions, credits, self-employment tax, or withholding.
| 2026 change | Why it matters | Record to gather |
|---|---|---|
| Freelance or business income increased | Profit can create both income tax and self-employment tax. | Year-to-date income statement, expenses, invoices, and payment records. |
| Stock, cryptocurrency, or other asset sale | A taxable gain can raise the annual estimate, often in one payment period. | Trade confirmations, basis records, dates, proceeds, and estimated gain. |
| RSU vest or stock-option exercise | Payroll withholding may not fully cover the resulting tax. | Vest or exercise statement, pay stub, and withholding details. |
| Bonus, commission, or second job | Added income can change the marginal tax rate and full-year withholding need. | Recent pay stubs and expected remaining compensation. |
| Roth conversion or retirement distribution | The taxable amount may increase income without enough withholding. | Custodian statement and any federal tax withheld. |
| Rental income or major expense change | Expected taxable rental profit may move up or down. | Rent ledger, deductible-expense records, and depreciation information. |
When you receive both employee wages and contractor income, keep their tax treatment separate. The ePaystubs W-2 versus 1099 guide explains why payroll withholding on one income stream may not cover tax on another.
How to Make a 2026 Estimated Tax Payment
You do not file the full Form 1040-ES package with an electronic payment. The form contains the worksheet and mail-in vouchers, while the IRS also provides online and account-based payment options.
Use the 2026 worksheet and your actual year-to-date records. Do not guess from gross revenue.
Use Direct Pay, an IRS Online Account, EFTPS, an approved card processor, or mail when appropriate.
Select estimated tax/Form 1040-ES and tax year 2026. Review identifying information before submitting.
Save the confirmation number, date, amount, method, and bank or card record.
IRS Direct Pay allows eligible individuals to pay from a bank account without signing in. The IRS advises users to keep the confirmation number. Card and digital-wallet processors charge fees, so review the current IRS payment page before choosing one.
An ePaystubs tool can help you estimate and organize a legitimate current-year Form 1040-ES using accurate information, but it does not transmit your tax payment to the IRS. You remain responsible for checking the figures and completing payment through an approved IRS method.
What If You Miss the September 15 Deadline?
Do not wait until January merely because September has passed. Recalculate the shortfall and pay as soon as practical. The IRS can apply an underpayment penalty when an installment is late or insufficient, even if you later receive a refund.
- Confirm the amount that should have been paid through September.
- Subtract payments and withholding already credited.
- Make the corrective payment through an appropriate IRS method.
- Reproject the remainder of 2026 and adjust the January payment or wage withholding.
- Keep every payment confirmation for return preparation and any Form 2210 calculation.
If you cannot pay the full amount, a partial payment can reduce the unpaid balance, but it does not automatically remove penalties or interest. If the numbers are substantial or an earlier payment period was affected, consider help from a CPA, enrolled agent, or tax attorney.
Special Estimated Tax Rules to Check
| Situation | What changes | Where to verify |
|---|---|---|
| Income earned unevenly | The annualized income installment method may support unequal payments tied to when income arrived. | Publication 505 and Form 2210 instructions. |
| Farmers and fishermen | Qualifying taxpayers have different percentages and payment timing; the regular September schedule may not apply. | 2026 Form 1040-ES and Publication 505. |
| Fiscal-year taxpayer | Due dates are based on the fiscal year rather than the calendar-year dates shown above. | Publication 505. |
| Nonresident alien | Form 1040-ES (NR) and different timing or calculation rules may apply. | Current Form 1040-ES (NR) and Publication 519. |
| Federally declared disaster | The IRS may postpone an estimated-tax deadline for eligible areas and taxpayers. | Current IRS disaster-relief announcement for the location. |
Do not assume that a news headline, neighboring county, or prior disaster notice covers you. Verify the eligible locations, affected taxpayers, covered deadlines, and postponed date in the current IRS announcement.
Use the ePaystubs 1040-ES generator to work through a current-year estimate using your real tax information. If additional wage withholding is part of the plan, prepare a current Form W-4, review every entry, and give it to your employer. These tools do not replace professional advice or transmit a payment to the IRS.
Frequently Asked Questions
Yes. September 15, 2026, is the third individual estimated tax payment due date for calendar-year taxpayers. The IRS calls the covered period June 1 through August 31.
Not always. Equal installments often produce a 25% September installment, but income changes, earlier underpayments, the annualized income method, withholding changes, and special rules can change the amount due.
Possibly. The IRS says wage earners may avoid estimated payments by asking an employer to withhold more. Whether that works for you depends on the shortfall, remaining paychecks, payroll processing date, and full-year estimate. A direct payment may still be needed.
Form W-4 Step 4(c) is for an additional dollar amount withheld from each paycheck. Give the completed form to your employer. Do not send it to the IRS.
An underpayment penalty may apply for the period the payment was late or insufficient. Paying promptly can reduce the continuing shortfall, but it may not eliminate a penalty already incurred.
No. Federal and state estimated taxes use separate rules and payment systems. Check the official revenue or taxation agency for every state where you may have a filing obligation.
Official Sources and References
- IRS: 2026 Form 1040-ES, Estimated Tax for Individuals
- IRS: Publication 505 (2026), Tax Withholding and Estimated Tax
- IRS: Estimated Taxes
- IRS: Publication 15 (2026), Employer’s Tax Guide
- IRS: Tax Withholding Estimator
- IRS: Direct Pay With a Bank Account
- IRS: Estimated Tax After a Large Gain or Lump-Sum Distribution
- IRS: Tax Relief in Disaster Situations
