@a-shlafer asked: "Turbotax autopopulated the number for "2023 Tax Liability for 2210 Purposes" for me, but I don't have an 2210 Forms from past years. Where did this come from"
For folks who had any tax liability (before payment) in 2023, TurboTax brings over a figure called "2023 tax liability for 2210 purposes", so it can tell if you paid enough tax throughout 2024 or in timely payments to avoid a 2024 underpayment penalty. It doesn't imply that a Form 2210 was used last year; it needs that figure to see if it needs to prepare a 2024 Form 2210.
Folks who are in the same Online account as last year, or using a desktop product and transfer from the *.tax2023 data file, and who had any 2023 tax liability (even when they paid it in full) have that 2023 figure transferred into 2024 for 2210 evaluative purposes. It's the 2023 figure before you actually made any payments. (I "think" the TurboTax figure essentially uses 2023 taxes less some types of 2023 credits, but it might be more complex than that.) In any case, TurboTax 2024 either asks for it, or as in your case, it transferred in automatically. It doesn't imply that you didn't pay 2023 taxes; it just wants to know what the liable amount was for 2023 so it can compare it to your 2024 payments. Here's why:
In the background as you prepare your return, TurboTax prepares a Form 2210 to see if you are liable for a 2024 underpayment penalty. As part of those calculations TurboTax uses a figure called "2023 tax liability for 2210 purposes". And on the Form 2210 one of the things it utilizes is comparing your payments that you made throughout 2024 to that 2023 tax liability in order to see if you paid enough in during 2024 to meet the minimum requirements to avoid an underpayment penalty for any quarter, and if you didn't, then to figure the penalty.
I don't know how you're preparing your return, but if you're using desktop TurboTax, you can go into Forms Mode, and way down in the left-column list of forms you can view the Carryover Worksheet, abbreviated as Carryover wks. On page 2, Line 6 of that Carryover wks it should show you 2 columns-- in the first column Line 6 shows what it transferred in this year for your "2023 tax liability for Form 2210 purposes", and the second column shows what it will use next year for your "2024 tax liability for 2210 purposes" when you prepare your 2025 return. NOTE: that 2nd column (2024) will continue to change as you continue to work on your return.
