Car business use calculated incorrectly in turbotax 2024?

[asdfg1234]

Why 27 (c) is only 48.54% when I entered 953 business miles and 1633 total miles? Shouldn't it be 953/1633=58.4%?

[asdfg1234]

This seems to be bug in turbotax. Line 9 should be calculated as Line 6 ($953) divided by Line 5c ($1636). Obviously, 48.54% is not correct answer for Line 9.

[SteamTrain]

@asdfg1234 

I haven't looked up the actual instructions, but the 48.54 % seems to be the result of multiplying the actual 58.4% x 10/12   (10 months of use in line 10b)    Maybe that's a (non-obvious)  background modification in the IRS forms instructions that isn't apparent.   But Like I said, I haven't looked up the actual IRS instructions that might detail that....or not.

[asdfg1234]

You are right, It appears the issue is tied to the number of months the vehicle is in service. For example:

1. With a purchase date of January 1, 2024, and all other factors unchanged, the business-use percentage calculates to 58% as I expected, which qualifies for the preferential depreciation method.

2. With a purchase date of December 30, 2024, under the same conditions, the business-use percentage drops to just 4.97%, which does not qualify for the preferential depreciation method.

This suggests that vehicles purchased late in the year are effectively penalized, since the business-use percentage must be much higher—closer to 95%—to be recalculated by TurboTax over 50% threshold on Line 9 of Turbotax Car and Truck Expense Worksheet (that gets put on 4562).

I also noticed that answering “Yes” to the question “Did you track the miles driven for personal use?” eliminates the purchase date as a factor. However, in TurboTax this option only appears when the vehicle is newly created. If the vehicle is simply edited, the question does not show up anymore—requiring the truck to be deleted and re-entered in order to access it. Screenshot here (edit&new workflow):

[AmeliesUncle]

As you had noticed, you need to go back through the questions and when it asks if you kept track of personal miles, say YES (or change the answer on line 10a of your second screenshot).

It was placed in service in 2024, so it was newly-entered this year.  I am unsure why it doesn't ask that again if you go through and edit it.

[asdfg1234]

Are there legal implications if I answer "kept track of personal miles" with "yes". 

I only kept records of work miles. Not personal. But I have odomoter reading from 12/31/2024.

Which means I would be fine if IRS insists that all miles that I can't prove in 2024 as business miles are classified as personal. But I don't think I would be able to provide list of personal trips I made in 2024.

So still fine to answer that question with yes?