You do not need a finished return to make a good payment. You need last year's return and ten minutes. The goal is to get close enough that interest is small, not to hit the number.

Estimate in three steps

  1. Take last year's total tax from Form 1040.
  2. Adjust for what changed. More income, add. A dependent aged out, add. A big loss, subtract. Bought a house, maybe subtract.
  3. Subtract what you have already paid in: withholding on your W-2s and 1099s, and any estimated payments.

What is left is your balance. Round up. Overpaying comes back as a refund. Underpaying costs 7 percent plus penalty.

How to pay so it counts as an extension

  • IRS Direct Pay from a bank account, free, choose "extension" as the reason and 2026 as the tax year. This files Form 4868 for you. Save the confirmation number.
  • EFTPS if you already have an account. Same idea, slower to set up.
  • Debit or credit card through an IRS-listed processor. Convenience fees apply. Also counts as an extension if you mark it that way.
  • Check with a paper Form 4868. Works. Slowest to prove.

If you cannot pay it all

Pay something. The failure-to-pay penalty and interest are computed on the unpaid part, so every dollar sent in April is a dollar that stops costing you. Then file the return and set up a plan.

Common mistake

Making the payment and tagging it as an estimated payment for 2027 instead of a 2026 extension payment. It lands in the wrong year, your 2026 balance shows unpaid, and unwinding it takes a phone call and months.

Ready to file it?

You can file a personal extension (Form 4868) or a business extension (Form 7004) online in a few minutes with TaxExtension.com, an IRS-authorized e-file provider operated by our publisher. The extension is automatic; the payment is still due on the original date.

Sources

  1. IRS, Direct Pay
  2. IRS, Pay by debit or credit card
  3. IRS, Failure to pay penalty