Simple Calculation of Federal Tax

@jaxgab 

For taxable income amounts less than 100,000, the IRS (and TTX) use the IRS Tax tables.  So the number TTX used is correct.   You can go to the IRS website and get the actual tables for 2024 there as a PDF file.  You'll see that the TTX number is correct for ordinary taxable income in the $50 range from 85,400 to 85,450....all the same tax amount.

Once you get around to entering all your numbers, the calculated tax value may be different from the tax tables. That can happen if you have Qualified dividends (box 1b on a 1099-DIV) or long term capital gains, because the tax tables are not directly used in that situation.

Thanks.  I see the $ 13,847 tax in the IRS Tax Table (PDF), which is for Taxable Income of $ 85,400 to $ 85,450.

If you don't have qualified dividends and long term capital gains, are you saying the IRS requires you to use IRS Tax Table if taxable income is less $ 100,000?

Correct.....for the situation you describe, you must use the tax tables.

 But, for the entire $50  taxable income range, the tax is the same....no recalcs required.

Can you imagine the chaos that would result if the IRS allowed everyone to calculate their tax using the various marginal rates....millions of folks are simply unable to do the math properly and would get it wrong.    Tables simplify it....at least until Cap Gains and Qualified Dividends get involved.