rjs
Level 15
Level 15

After you file

A payment with an extension is not an estimated tax payment (even though the amount you pay with the extension might be an estimated amount). Estimated tax payments are quarterly payments that you make during the year. The payment with the extension was made in July of the following year. What the IRS is saying is that you should have made quarterly estimated tax payments during 2019. The federal income tax is "pay as you go." You paid all the tax that you owed, but you didn't pay it soon enough. Estimated tax payments would be on Schedule 3 line 8.