federal taxable income went down in 2023 but federal tax went up significantly compared to 2022

[starfisht]

Our 2022 taxable income was 145K. Our 2022 tax was slightly less than 17K.

Our 2023 taxable income was 142K. Our 2023 tax is 21K.

So our taxable income went down and our tax went up significantly. I'm not of any tax law change that would account for this.   Possible explanation?

[BillM223]

We in the Community cannot see your private tax data.

We would encourage you to examine your 2022 and 2023 1040 forms line by line until you find an unexplained difference. Then you can come back here and ask us about it.

There are just too many possibilities to list here.

[starfisht]

I see that I was under the mistaken impression that, to calculate the tax liability, TT applies the taxable income on 1040 line 15 to the same federal tax table and, depending on the filing status, comes up with the tax on line 16. But now I see that there are several tax tables.

In 2022 it used the "Schedule D Tax Worksheet" and in 2023 it used the "Qualified Dividends and Capital Gains Tax Worksheet". So I was comparing apples to oranges. Even though it seems strange that a lower taxable income results in a 25% higher tax, I'll assume TT is correct because I know that the input I gave it is correct.

[Hal_Al]

Yes, capital gains and how they are taxed is the primary explanation for what you are experiencing. 

A side by side comparison of the  2022  "Schedule D Tax Worksheet" and the  2023 "Qualified Dividends and Capital Gains Tax Worksheet" should explain the difference. 

The bottom lines, on each worksheet, has a comparison of the actual tax (with capital gains rates) vs. the "coulda been"  tax from the tax  table.