How to Pay Estimated Taxes Online by September 15

You can open IRS Direct Pay, enter your bank information, and finish a payment in a few minutes. The harder part often happens before that: deciding whether you owe anything, choosing an amount, and trusting that you selected the right IRS labels.

That uncertainty is reasonable. The September payment is called the third quarterly payment, yet it does not line up with a normal three-month quarter. It covers income received from June 1 through August 31. If taxes were not withheld from that income, September 15, 2026, may be the next federal deadline that matters to you.

There are two separate jobs here. First, make a reasonable estimate. Then send the payment to the correct IRS account. The first job deserves more time than the bank transfer.

Who usually needs to pay estimated taxes?

Estimated taxes commonly apply when you receive income without enough federal tax withheld. That may include income from:

• Freelance or contract work
• A side business
• Rent
• Interest, dividends, or capital gains
• Royalties
• Retirement distributions with limited withholding

Estimated payments can cover federal income tax and self-employment tax. A Form 1099 is a useful signal, but it does not settle the question. Your full-year tax picture matters more than any one form.

For individuals, estimated payments may be required if you expect to owe at least $1,000 after subtracting withholding and refundable credits. You may avoid an underpayment penalty if your withholding and timely estimated payments meet a safe harbor, generally:

• 90% of your current-year tax, or
• 100% of your previous year’s tax

A 110% prior-year threshold can apply at higher income levels. The 2026 Form 1040-ES instructions explain the qualifications and exceptions.

This is why blanket advice like “You earned freelance income, so you need to pay quarterly taxes” can be unhelpful. Someone with a W-2 job may already have enough withheld to cover modest side income. Someone else may owe an estimated payment after selling an investment, even if they have never freelanced.

Sending one-fourth of last year’s balance is tempting because it feels concrete. Sometimes it is a workable estimate. Sometimes it is badly out of step with what changed this year.

Before calculating, gather four numbers:

1. Your 2026 income so far
2. Your expected income for the rest of the year
3. Federal tax already withheld
4. Estimated payments already submitted

A notebook page is enough. Write down what you know, mark what is still uncertain, and resist the urge to make the numbers look more precise than they are.

If your income has changed significantly, use the Form 1040-ES worksheet, tax software, or a tax professional. An estimate based on actual income through August will usually be more useful than a number copied from last year.

How to pay through IRS Direct Pay

IRS Direct Pay lets individuals transfer money from a checking or savings account without a payment fee. The IRS Direct Pay instructions for estimated taxes identify it as an online payment option for Form 1040-ES.

The screens may change slightly, but the basic process is:

1. Open IRS Direct Pay from IRS.gov.
2. Choose Estimated Tax as the reason for payment.
3. Confirm that the payment applies to 1040-ES.
4. Select 2026 as the tax period.
5. Verify your identity using information from a previously filed federal return.
6. Enter the payment amount and bank account details.
7. Choose the payment date.
8. Review each field before submitting.
9. Save the IRS confirmation number.

The wording around “quarter” causes more confusion than it should. Direct Pay generally asks for the tax year instead of offering a separate third-quarter button.

For a September 2026 payment, pause and check these three entries:

• Reason for payment: Estimated Tax
• Apply payment to: 1040-ES
• Tax period: 2026

If another IRS payment service shows an installment field, choose the third estimated-tax installment for 2026.

Do not choose Balance Due or Extension because the wording seems close enough. Those are different payment types. The money may leave your bank successfully and still require follow-up if it was sent under the wrong label.

Before closing the page, save or print the confirmation. After the scheduled date, check your bank account to make sure the withdrawal cleared. That proof matters if the payment is rejected, delayed, or applied somewhere unexpected.

Why September does not match a calendar quarter

For calendar-year individuals, the 2026 federal estimated-tax dates are:

• April 15: for income from January 1 through March 31
• June 15: for income from April 1 through May 31
• September 15: for income from June 1 through August 31
• January 15, 2027: for income from September 1 through December 31

The IRS estimated-tax schedule confirms that income received from June 1 through August 31 falls into the payment period due September 15.

For the September 2026 payment, IRS Direct Pay guidance says to submit by 8 p.m. Eastern on September 14 to meet the September 15 deadline.

Paying earlier is not always realistic. You may be waiting for a client payment or still working through uneven income. Even so, one extra business day can give you time to catch an incorrect bank account number or respond to a rejected transfer.

Dates may shift in other years when deadlines fall on weekends or federal holidays. Disaster relief can also change deadlines for affected taxpayers.

What if you missed the payment date?

Missing the deadline can make the whole task feel less urgent because it is already late. Unfortunately, waiting until January or until you file your return may increase the cost.

A practical response is to pay as soon as you can. An underpayment penalty may apply based partly on the amount underpaid and how long it remained unpaid. Once tax is assessed and remains unpaid, interest may also apply.

That does not mean a tax payment should automatically come before rent, utilities, food, or medication. If paying the full estimate would put essential expenses at risk, look at the tradeoff clearly. A partial payment may reduce the underpaid amount, although it will not satisfy the full estimated-tax requirement.

Income timing can also affect the calculation. Form 2210 may help when income arrived unevenly during the year. A freelancer who earned most of the year’s income in July, for example, should not necessarily be treated as if the money arrived evenly starting in January.

The form’s annualized income method can account for that timing. Form 2210 is also used for certain penalty-waiver requests, but filing it does not automatically remove a penalty.

Safe harbor rules may prevent a penalty even when your current-year estimate was off. The result depends on prior-year tax, current-year payments, income, filing status, and whether the previous return covered a full 12 months.

It also helps to name the problem correctly. An unpaid balance from an already-filed return is different from a current estimated payment. If you are dealing with both, review what to do first when an IRS bill is unaffordable and how an IRS payment plan works after missed taxes.

Keep those payment types separate. Money intended for 2026 estimated taxes should not accidentally be directed to an older balance.

A workable plan for September

Start with the four numbers: income so far, expected remaining income, federal withholding, and estimated payments already made. The Financial Snapshot can help you check the broader cash picture before money leaves your account.

Then take the next steps in order:

1. Confirm whether a payment is likely due. Use Form 1040-ES, tax software, or professional help if the answer is not clear.
2. Choose an amount you can defend. If the full estimate threatens essential expenses, acknowledge that constraint rather than ignoring it.
3. Select Estimated Tax, 1040-ES, and 2026.
4. Review the bank details. A good estimate cannot fix a rejected transfer.
5. Save the confirmation number with your 2026 tax records.
6. Check that the withdrawal clears.
7. Add January 15, 2027, to your calendar for the fourth payment.

For later payments, EFTPS and an IRS online account are alternatives to Direct Pay. EFTPS requires enrollment, so it is better to arrange before the next deadline. If you also have a W-2 job, increasing federal withholding through Form W-4 may reduce or eliminate separate estimated payments.

You do not need to solve your entire tax year at once. For September, the useful target is smaller: make a reasonable estimate, label the payment correctly, and keep proof that you sent it.

Then check your state. Federal payment guidance does not cover state estimated taxes, and your state may use different dates, calculations, and payment systems. Finishing the federal payment is progress. It is not necessarily the last tax task on the list.