I'm trying to locate a worksheet that breaks down the detail behind the number on line 16 "Tax" (Form 1040) to see exactly how this number was calculated, but I can't find anything. The Form 1040 Worksheet also just has the one lump sum number. Thank you.
Your tax due is not shown on line 16. If you have tax due for your 2021 tax return it is on line 37. Do you have an amount on line 37?
To see the method that your tax is calculated go to View->Forms from the top menu, At the top of the list of forms you would see 1040 WKS (worksheet) or something similar. There is a section "Tax Smart Worksheet" in this form where you can see the method used for the tax calculation. If it is the Tax table you can get that from IRS Pub 17. Mine used the "Qualified Dividends and Capital Gain Tax worksheet" which is also listed as one of the forms abbreviated "Qual Div/Cap Gn, (if it is used for tax calculation).
TurboTax fills tax due on line 16 of the 1040. TurboTax does that based on your input in the program interview. If you're doing a form by hand, or online fillable, line 16 is usually looked up in the tax table, based on the taxable income on line 15.
TT provides this information on the "1040/1040SR Wks" [should be the 1st worksheet in the forms view]. Specifically, refer to the "Tax Smart Worksheet" which is located partway down the form [this section is clearly identified]. The section lists the 7 possible sources of the tax computation and identifies which one is used [see the "X" to the right of the method used]. The 7 possible sources of the tax calculation are:
1. Tax Table
2. Tax Computation Worksheet
3. Schedule D Tax Worksheet
4. Qual Divs and Cap Gain Tax Worksheet
5. Schedule J
6. Form 8615
7. Foreign Earned Income Tax Worksheet
In addition to the above, the Tax Smart Worksheet lists a number of "additional tax worksheets" which may have been used in your tax calculation.
Hope this helps.