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March 6, 2024
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Turbo Tax Basic Tax Rate Calculation Check

  • March 6, 2024
  • 2 replies
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I entered several Income numbers on a W2 to compare TurboTax output to Smart Asset and an excel function I wrote.  Smart Asset and my numbers always match, but TurboTax is off by some number of dollars.

Does anyone know why?  I did a similar test last year and recall getting similar deviations.  Didn't follow-up at that time.

 

One of the numbers is correct, the last one.  It is a different tax rate though.

 

IncomeDeductionTurbo TaxSmartAssetMy number
8925027700694969466946
10000027700823982368236
12000027700109271092110921
11445027700997399709970
11450027700997999769976
52000027700116094116094116094

 

Thanks,
Greg

    Best answer by dmertz

    TurboTax's numbers are correct because for taxable amounts up to $100,000 one is required to use the Tax Table which produces taxable amounts based on $50 increments of income in the ranges that you are testing (except for $520,000 where you actually see agreement) and the tax is based on the midpoint of the step.  If you add $25 to each of your income amounts you should see agreement.  In other words, where there is disagreement the error is in both your spreadsheet result and in the result from SmartAsset.

     

    Also, in your spreadsheet, use TRUNC((income-deduction)/50,0)*50+25 in place of income minus deduction when income minus deduction is $100,000 or less.  (This won't be quite right at lower taxable income amounts where the table uses $25 income steps.)

    2 replies

    gwaddogAuthor
    March 6, 2024

    The numbers were all for Married Filing Jointly.  Tx

    DawnC
    Employee
    March 6, 2024

    Rounding issues, maybe.   Intuit works to ensure the accuracy of the calculations on every form prepared using the Services. The TurboTax Accurate Calculation Guarantee is for the lifetime of your 2023 individual tax return, which Intuit defines as seven (7) years from the date you filed it using TurboTax Online.

     

    100% Accurate Calculations Guarantee

     


     

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    gwaddogAuthor
    March 6, 2024

    A rounding error of $1 may be acceptable, but these are in the range of $3-6.  Turbo Tax tax calculation is yielding a higher amount of tax people owe.  I would think you would want to investigate a bit.  Here is yet a 3rd example of calculations which are the same as Smart Asset and my other formula.  These are done purely in Excel.

     

      Income89250100000120000114450114500520000
      Deduction277002770027700277002770027700
    Married Filing JointlyTaxable Income6155072300923008675086800492300
    2200010%0000000
    8945012%2200694682360997099760
    19075022%102940010921000
    36420024%32580000000
    46250032%74208000000
    69375035%10566400000116094
     37%186601.5000000
      Tax Total694682361092199709976116094
      Turbo Tax Tax Total694982391092799739979116094
      Turbo Tax Over Tax Calc $      3.00 $      3.00 $      6.00 $      3.00 $      3.00 $           -  

     

    Thanks for having someone check the Turbo Tax Algorithm which appears to be off in certain Tax percentages.

    Happy to send the Excel to someone who will look into it.

    dmertzAnswer
    Employee
    March 6, 2024

    TurboTax's numbers are correct because for taxable amounts up to $100,000 one is required to use the Tax Table which produces taxable amounts based on $50 increments of income in the ranges that you are testing (except for $520,000 where you actually see agreement) and the tax is based on the midpoint of the step.  If you add $25 to each of your income amounts you should see agreement.  In other words, where there is disagreement the error is in both your spreadsheet result and in the result from SmartAsset.

     

    Also, in your spreadsheet, use TRUNC((income-deduction)/50,0)*50+25 in place of income minus deduction when income minus deduction is $100,000 or less.  (This won't be quite right at lower taxable income amounts where the table uses $25 income steps.)

    gwaddogAuthor
    March 6, 2024

    Thanks for the detailed answer.