Do estimated taxed paid in Jan 2018 count as 2017 or 2018 taxes paid?

[andmill03]

Paid estimated CA state and Federal taxes jan 15 2018. Are these the  final payments for 2017 or the first for 2018?

[JulieCo · Accepted solution]

Yes, estimated taxes paid in January 2018 by the January due date count as 2017 tax payments.  

But also note, if you itemize deductions, the STATE taxes paid in January 2018 will not be included in the 2017 taxes paid amount line on Schedule A.  But they do count on your state return as 2017 taxes paid, and can count as state taxes paid if you itemize on your 2018 federal return.