I prepaid my 2018 property tax on top of 2017's one in 2017. I added 2018's one in "additional property tax on your main home" section, but Federal tax remains same.Why?

[Woodman]

I live in Ohio and prepaid property tax around $6000 for 2018 at the end of 2017, on top of 2017 property tax already paid in early 2017.  In turbo tax, I added 2018's property tax in the deductable section, "additional property tax on your main home" field, since 2017 property tax seemed to be already counted.  I itemized the deduction, so I expected an increase of my tax return, but total amount of Federal or Ohio tax return did not change.  Why...?  Isn't it counted as deduction...?

[SweetieJean]

AMT?

[Woodman]

Yes, AMT is applied.  Then the property tax would not be deducted...?  Probably I do not fully understand what would happen when AMT applied...

[AnnetteB · Accepted solution]

No, with Alternative Minimum Tax (AMT) property tax is not deductible. 

To learn more about AMT, take a look at Alternative Minimum Tax: Common Questions.