When I was entering itemized deductions the Federal tax amount kept dropping until i got to property taxes and then the tax did not drop any further. Why is that?

[jscvermont]

Married, filing jointly.

The property tax was 10947.

Total itemized deductions was 33939.

Tax was 46073.

Alternative minimum tax was 4603.

Total tax was 50981.

[AnthonyC · Accepted solution]

The result you are experiencing is from the Alternative Minimum Tax.  

While the rules and calculations for the AMT are quite complex, the basic result is the tax benefits you receive from certain deductions (like property taxes) are then wiped out by an increase in tax liability in the form of the AMT.  So, as you enter more itemized deductions, your AMT liability increases proportionately causing there to be no effect on your refund total.  You can read more information about the AMT at these links -

What is the Alternative Minimum Tax?

Alternative Minimum Tax - Common Questions