A "simple" income tax formula???

I'm retired and have constructed a 25 year budget in Excel to help assess what investment returns and strategies will ensure that I don't outlive my savings. I've developed two formulae (regular and AMT) to estimate my Federal tax burden, recognizing of course that tax rates will inevitably rise to pay for all the current government spending. But I don't fully trust my formulae to give me a reliable estimation of my tax burden.

Are there standard Excel formulae available for computing taxes, assuming that you've already computed your taxable income and some of the more routine deductions and adjustments (e.g., mortgage and property tax interest, state income taxes, etc.)?

Below are the two formulae I've been using. I won't bother to define the cell references since I'm not necessarily asking for a critique of my current formulae but rather any references to more reliable, pre-existing ones.

Regular Federal income tax: =MAX(MAX(((IF((J18)<=16050,((J18)*0.1),0))),(IF((J18)<=65100,(1605+(J18-16050)*0.15),0)),((IF((J18)<=131450,(8962.5+(J18-65100)*0.25),0))),((IF((J18)<=200300,(25550+((J18)-131450)*0.28),0))),((IF((J18)<=357700,(44828+((J18)-200300)*0.33),0))),((IF((J18)>357700,(96770+((J18)-357700)*0.35),0)))),0)

Federal AMT income tax: =(SUM(J14:J16,J22)+(J16+J22)-MIN((0.8*(SUM(J14:J16,J22))),((J17-159950)*0.03))-69950)-0.29*(SUM(J14:J16,J22)+(J16+J22)-MIN((0.8*(SUM(J14:J16,J22))),((J17-159950)*0.03))-69950)-3500
Thanks for any guidance you can provide.

Bob

Hello Bob,

If you want to calculate total tax when there are several bands try using this method here

Post back if you need any help applying it.....

Have a look at this sample...

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Thanks for the replys, DLL and yurttas. I haven't used the SUMPRODUCT function but it basically achieves what I've been doing with MAX and IF functions. And, yurttas, the example you referenced is even more rudimentary than the one I'm using.

I guess I had assumed that someone would have developed a more sophisticated income tax formula that not only calculated the impact of progressive tax rates but also included such things as a) the roll-off for exemptions and standard deductions as taxable income levels increase, b) AMT, c) capital gains rates, etc.

Any other leads?

Bob