I remember turbo tax estimating my tax penalty for 2018 but when I look at 1040 line 23 it shows it was not calculated. Now I received a tax penalty from the IRS.

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Under most circumstances the IRS default procedure of receiving your tax return, calculating underpayment penalty interest and sending you a bill to be paid within 30 days is fine and costs you no more or less than if you had TurboTax fill out the short form 2210 and add that amount to your original tax payment.  Plus you get a few more weeks of having that money in your own checking or savings account.

The exceptional circumstance, which I deal with in some years, is when your income comes in unevenly throughout the year.  In that case, the complicated Schedule AI of Form 2210 may reduce or eliminate the penalty.