It depends on what kind of income you have. There are like 7 different ways to figure the tax.
See the IRS worksheet on 1040 page 36 for how the tax is figured. Turbo Tax uses the same worksheet.
https://www.irs.gov/pub/irs-pdf/i1040gi.pdf
Even though it shows up as income on the first page,if you have capital gains or qualified dividends the tax is not taken from the tax table but is calculated separately from schedule D. The tax will be calculated on the Qualified Dividends and Capital Gain Tax Worksheet. It does not get filed with your return. See this FAQ
https://ttlc.intuit.com/community/forms/help/form-1040-line-11-amount-is-less-than-standard-irs-tax-...
In the online version you need to save your return as a pdf file and include all worksheets to see it.
