My tax liability is incorrectly calculated (MfJ). Turbo tax has taxable income of 278554 with tax liability of 55587. 1040 Tables say this should be 55012. Why different?

[jerjackson]

MfJ - married filing Jointly.
278,554 x 0.24 - 11841 = 55,012
Turbo Tax shows 55,587 liability for difference of 575 dollars.

[JeffreyR77]

Tax liability is calculated based on various components only one of which may be the tax tables.  With the taxable income stated, not all of the income is necessarily taxed at a flat 24%. 

At the stated income level, you may be subject to additional Medicare tax or net investment income tax. 

Your tax liability could also be higher if your withholding was not high enough to avoid underpayment penalty.  

[CyclistFamily]

I have a similar issue and the discrepancy is $30.00 and I am married filing jointly.

I have created an Excel spreadsheet that mimics the tax return since 2014.  For tax years 2014 to 2019, I have been exact with one exception; off by $1.00.  That is because the Excel spreadsheet does not round up or down.  If I entered $4,546.89, I keep it.  IRS and all tax software will store it as $4,547.

For tax year 2020, I am off by $30.00.

I understand the 10%, 12% and 22% tax brackets; which I used for taxable income.  I have qualified dividends, taxed at 15%.

I looked all entered values within Turbo Tax and the Excel spreadsheet; they are exact taking into account the "rounding up/down".

This posting from a tax expert stated, some components are taxed at different rate.  Can you explain which components are not taxed using the gradient scale, 10%, 12% and 22% for ordinary income and 15% for qualified dividends?

I think that Turbo Tax is using an incorrect deduction and/or tax bracket limits; ie 10% at $19,750.

Thanks in advance

[CyclistFamily]

Oops, I forgot to include; my tax liability within my Excel spreadsheet states $X.00 and TurboTax states $X minus $30.00.  So I am getting $30.00 more as a refund.

My taxable income does not hit any "fees"/"penalties"/etc.

[jerjackson]

Thanks Jeffrey. I did find out that the delta I was seeing was from the additional Medicare tax being applied for joint incomes over 250k. I am still confused as to why turbo tax can’t provide that information up front. I had to dig through a whole bunch of different links to find out what this ‘other tax’ was coming from and how it was being calculated and why. None of the help boxes worked.