I use the Case Study Spreadsheet (CSS) personally and really like it (thanks
@MDM, I probably owe you a beer or coffee). I will mention to OP that the way the IRS talks about dividends, how they're reported on tax forms, and how they are entered into the CSS might be a bit confusing to someone the first time. So make sure if you use that tool that you understand what's going on. The best way I have found to do this is to enter the numbers for the prior tax year (2024 in this case) from your tax return into the CSS, and make sure that the CSS gives you the same tax liability as shown on your 1040. Then you can hopefully switch to tax year 2025 and enter the proper numbers in the proper place.
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@MDM, I don't recall details, I have to figure it out again for myself every December, but I think users might not be able to enter ordinary and qualified dividends directly into the CSS. IIRC I have to enter one or the other of those into the columns on the left, then do the appropriate math and enter the difference in another cell somewhere. I hope you know what I'm referring to.)