Taxes

Form 1040-ES: How to calculate and pay estimated taxes for 2026

Published October 23, 2026 14 min read

Form 1040-ES helps you estimate and pay federal tax during the year rather than waiting until you file your annual return. A careful estimate starts with income, withholding, credits, and the right payment schedule.

• You may need estimated payments when income is not covered by withholding and you expect to owe tax.
• Use the Form 1040-ES worksheet to estimate your full-year tax, then account for withholding and credits.
• The 2026 installments have four deadlines, with the last one falling in January 2027.
• Your income may arrive unevenly, so update your estimate as the year unfolds.
• Keep payment confirmations and records so you can reconcile estimates on your annual return.

What Form 1040-ES is and who uses it

Form 1040-ES is an IRS worksheet and set of payment vouchers for estimating and paying federal income tax during tax year 2026. You may need it when income arrives without enough tax withholding. The form helps you estimate what you owe for the year and divide payments across the applicable installments. It does not replace the Form 1040 you file after the year ends.

How estimated payments fit into your annual tax return

Estimated payments are prepayments toward the federal tax you expect to report on your annual return. You calculate the year’s likely tax, subtract withholding and refundable credits, then pay toward any remaining amount during the year. When you file, you compare total payments with the actual tax on your return. A balance due or refund depends on that final comparison, not on the worksheet alone.

The IRS provides the 2026 Form 1040-ES for individuals to estimate tax and make payments. The amount you pay is credited toward your tax-year 2026 return, so keep it distinct from a payment for another year. The IRS overview of Form 1040-ES explains how estimated tax applies to income without withholding.

Income that may require estimated tax payments

Estimated tax can apply to taxable income that does not have enough federal tax withheld. Examples include self-employment income, interest, dividends, rents, and certain other taxable income. If you resell goods as a business, you generally need to estimate tax from your profit rather than treating gross sales as the amount you earned. For a broader explanation of taxable income and reseller profit, see Reseller tax basics.

A payment form from a marketplace is not a measure of your tax due. A 1099-K reports gross payments, which may not reflect refunds, fees, postage, or inventory costs; the 1099-K explained guide covers how to reconcile those amounts. Whether your sales produce taxable profit is a separate question from whether you receive an information form.

When employees and self-employed taxpayers may need to pay

You may need estimated payments even if you also have a job with withholding. For example, withholding from wages may not cover tax on a side business, investments, or rental income. If you work for yourself, there may be no employer withholding on your business earnings, so you may need to plan for both income tax and self-employment tax.

For a reseller, records of sales, refunds, inventory costs, and expenses give you a more useful starting point than payout totals. FlowLister writes eBay listings from item photos, with a price taken from sold listings; it does not prepare taxes or keep books. Keep your tax calculations and supporting records separately, regardless of how you create listings.

Determine whether you need to make estimated payments

You generally need to consider estimated payments when you expect to owe tax after withholding and credits, and your payments during the year may not meet IRS thresholds. The calculation is based on your expected tax for the year, not only on the amount of income you received. Review the estimate when earnings or withholding change. That makes the decision less of a once-a-year guess.

Estimate your tax after withholding and refundable credits

Start with an estimate of your total federal tax for tax year 2026, including the taxes that apply to your income. Then subtract expected federal withholding and refundable credits. What remains is the estimated balance you need to compare with the IRS payment rules. Withholding from a paycheck counts in this calculation, even if the income that prompted the estimate came from a separate activity.

This is also where a realistic income estimate matters. If your gross receipts include refunds or sales proceeds that are offset by inventory and business expenses, do not treat the full gross amount as profit. Keep the underlying records close at hand so you can explain how you arrived at the estimate.

Apply the expected-balance and payment thresholds

For tax year 2026, the IRS generally says you need estimated payments if you expect to owe at least $1,000 after withholding and refundable credits, and your withholding and credits are less than the required share of your tax. The IRS rule compares withholding and credits with 90% of your expected tax for tax year 2026 or 100% of the tax shown on your 2025 return, using the smaller amount. See the IRS estimated tax rules for the complete conditions and exceptions.

The thresholds are a test for whether you may need to pay during the year; they do not change the tax you ultimately owe. If your income is high enough to trigger the special prior-year rule, check the IRS instructions for the applicable percentage rather than relying on a general estimate. The quarterly estimated-tax guide provides additional context on payment planning for resellers.

Compare current-year tax with prior-year safe harbor rules

The prior-year comparison can be useful when you cannot predict your tax-year 2026 income precisely. Look at the tax shown on your 2025 return, then compare it with your current-year estimate and expected withholding. The IRS rule can require a higher prior-year payment percentage for some taxpayers, so use the Form 1040-ES instructions and the IRS estimated-tax guidance rather than assuming the general percentage applies to you.

A prior-year safe harbor is a payment planning rule, not a forecast of your actual tax bill. Your tax-year 2026 return still reconciles your final income, deductions, credits, withholding, and payments. If your circumstances are unusual or the numbers are close to a threshold, professional advice can help you apply the rule correctly.

Estimate your 2026 tax with Form 1040-ES

To estimate your tax for tax year 2026, project your income and adjustments for the full year, then use the Form 1040-ES worksheet to calculate the expected tax and installment amounts. Begin with records you can support rather than a guess based on recent deposits. The estimate is allowed to change as the year develops. A careful first pass is more useful than false precision.

Project income, deductions, and credits

Estimate the income you expect to receive during tax year 2026 from all relevant sources, then account for deductions and credits that may apply. If you run a resale business, distinguish sales from profit: refunds, the cost of items sold, fees, postage, and other allowable business expenses can affect the result. Do not subtract the cost of inventory that remains unsold as though it were already an expense of sold goods.

A practical way to organize the estimate is to gather the records that explain the movement from gross receipts to taxable income. For a reseller, that may include:

• Sales and payment reports from each marketplace.
• Refunds, returns, and customer credits.
• Records for inventory purchased and items sold.
• Fees, postage, and other business expenses.

Use those records to update your projection, not to assume every deposit is taxable profit. If you want a rough cross-check of business income and self-employment tax, the self-employment tax calculator estimates tax from entered figures; it is not a tax return.

Include income tax and self-employment tax

If you have self-employment income, your estimate may need to include both income tax and self-employment tax. Form 1040-ES asks you to consider the taxes that apply to your situation, so do not stop after estimating income tax alone. For the applicable treatment, consult the IRS instructions for the current forms and schedules, including Schedule SE.

The distinction matters for resellers who report business profit: a rough set-aside based only on income tax can leave out another part of the expected federal bill. The 2026 Form 1040-ES worksheet gives you a structure for estimating your total liability. If you have wages as well, include expected withholding before deciding how much additional tax to pay.

Use the worksheet and update estimates when circumstances change

Work through the Form 1040-ES worksheet using the information available to you, and keep a copy of the assumptions behind the estimate. The worksheet is a planning tool, so revise it if income, deductions, credits, or withholding change materially. A midyear adjustment can be more useful than continuing to pay installments based on an outdated projection.

For a reseller, a simple update may mean reconciling marketplace reports with your own records before changing the estimate. A 1099-K may show gross payments rather than profit, so account for costs and refunds when projecting taxable business income. Save each version of the estimate so you can see what changed and why.

Understand 2026 due dates and installment rules

Tax-year 2026 estimated payments follow four installment deadlines, and the payment schedule is not four equal three-month periods. The dates are set out in the 2026 Form 1040-ES, which also includes the payment vouchers. If you have uneven income, special rules may let you align payments more closely with when income was received. Check the applicable instructions before changing the installment amounts.

Mark the four estimated tax payment deadlines

For tax year 2026, the Form 1040-ES schedule lists these federal estimated-tax due dates. Confirm the schedule in the IRS Form 1040-ES, especially if a deadline may be affected by a weekend or holiday.

These are the standard dates for tax-year 2026 installments, with the final payment due in the following calendar year. Mark each one and record when you actually submit a payment. If you need the full schedule and payment details, consult the IRS form rather than relying on a calendar reminder alone.

Account for uneven or seasonal income

You do not have to assume that income arrives evenly throughout the year. If your income is seasonal or changes sharply, the annualized income installment method may help calculate required payments based on when income was earned. The method can involve additional calculations and records, so review the Form 1040-ES instructions before using it.

For a seller whose business grows or slows during the year, keep dated records of receipts and expenses instead of trying to reconstruct the pattern later. Then revisit the estimate when you have a clearer picture of the year. An estimate based on actual timing can better reflect an uneven year than dividing a rough annual total into equal pieces.

Check how weekends and holidays affect a deadline

When a standard payment deadline falls on a Saturday, Sunday, or legal holiday, the IRS generally treats a timely payment as one made on the next business day. Confirm the rule for the specific payment and date using IRS guidance, especially if disaster relief or another special extension may apply. Do not assume that an extension to file a return also extends a payment deadline.

A payment confirmation or postmark can help establish when you submitted an installment. Keep that record with the payment amount and the tax year it applies to. If your payment is close to a due date, use an IRS payment channel that gives you a confirmation you can save.

Submit payments and use Form 1040-ES vouchers

You can submit estimated tax payments electronically or mail a check with the correct Form 1040-ES voucher. The IRS form explains the payment options and includes vouchers for taxpayers who pay by mail. Choose one method for each installment and make sure the payment is designated for tax year 2026. A careful payment record helps prevent confusion when you file.

Choose an IRS electronic payment method

The IRS lists electronic options for paying estimated tax, including IRS Direct Pay and other approved payment services. Follow the IRS instructions to select the payment type and tax year, then save the confirmation number or receipt. Electronic payments can be convenient, but you still need to check that the payment was applied to the intended account and year.

Use the payment options described on IRS.gov rather than a link from an unexpected message. If you are making an additional payment after revising your estimate, identify it as an estimated-tax payment for tax year 2026 so it is not confused with a balance due for a different year.

Mail a check with the correct payment voucher

If you pay by mail, use the voucher for the installment and tax year shown in the Form 1040-ES instructions. Make the check payable as directed by the IRS and include the identifying information requested on the voucher. Send it to the address listed for your location and payment type; addresses can differ, so do not rely on an old envelope or a prior-year form.

Before sending it, check that the check amount matches the amount you intend to pay and that the voucher identifies the right tax year. Keep a copy of the voucher and check, along with proof of mailing. The IRS form is the place to confirm current mailing instructions.

Keep confirmations and apply payments to the correct tax year

Keep a record for each estimated payment, whether you paid electronically or by check. Note the submission date, amount, payment method, confirmation or mailing evidence, and tax year. These details make it easier to resolve a payment that does not appear where you expect it to.

When you file your annual return, report the estimated payments in the appropriate place and compare them with IRS account records if needed. If you make payments for more than one tax year, label each record clearly. That small habit can prevent an otherwise avoidable mismatch at filing time.

Avoid underpayment problems and keep records

You can reduce underpayment problems by estimating carefully, paying on time, and retaining records that support your calculations. The IRS may assess an underpayment penalty when required installments are not paid in sufficient amounts or on time, even if you later pay the balance with your return. The calculation depends on the amount and timing of the underpayment. Review the IRS rules rather than assuming a refund or balance due tells the whole story.

Understand underpayment penalties and safe harbor rules

The underpayment penalty is generally based on how much tax was unpaid and for how long, subject to the IRS rules and exceptions. Meeting an applicable safe harbor can help you avoid the penalty, but it does not necessarily mean your actual tax bill will be fully paid. Use the 2026 Form 1040-ES instructions and the IRS estimated-tax page to assess the requirements for your situation.

Keep the records behind your estimate, including income reports, withholding statements, credit documentation, payment confirmations, and any revised worksheets. If you are a reseller, also retain records that support how you calculated profit from sales, refunds, inventory, and expenses. The IRS recordkeeping guidance explains why supporting documents matter.

Adjust withholding or make an additional estimated payment

If your estimate shows that you may fall short, you can consider increasing withholding from wages or making an additional estimated payment. Withholding may be a practical option if you have wage income, while a separate payment may fit better if your income is primarily self-employment or investment income. Compare the choices against your updated estimate and the IRS rules for tax year 2026.

Do not wait until the final installment if you already know that your income or withholding has changed. Recalculate using the current information, then decide whether to adjust a later payment or withholding. Keep a note of the change so that your next estimate starts from the updated figures.

Reconcile estimated payments on your Form 1040

When you prepare your annual Form 1040, compare the estimated payments you made with the total tax reported on the return. Include the correct payment records and check that each amount is assigned to the right tax year. If your records and IRS account information do not agree, investigate the difference before concluding that a payment was missed.

The reconciliation is the final check on the estimates you made during the year. Your tax return reflects actual income and allowable deductions and credits, while Form 1040-ES was based on a projection. Keep the supporting worksheet and payment confirmations with your tax records so you can explain the difference between the estimate and the final result.

Conclusion

Form 1040-ES gives you a way to estimate federal tax and pay it during tax year 2026, but the estimate should follow your real income, withholding, and records. Revisit it when circumstances change, use the IRS schedule and payment instructions, and save proof of every installment. If you want to check a reseller-focused estimate, run your figures in the free calculator before deciding what to pay.

This is general information, not tax advice. Talk to a CPA or enrolled agent about your situation.

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