I used the Fed tax What-IF page in TT2017 and specified to use 2018 tax rates. The sheet grabs numbers from your return but you can over-ride them with what you think your 2018 numbers will be. Works very nicely. Only problem is there is nothing for New York State. BUT - I never knew the taxcaster was there - that appears to do the same thing effectively - great for TT for doing it. I won't say what I think of the Infernal Revenue for not doing it.
