Can you overpay 2017 state tax now to get a bigger Federal itemized deduction for year 2017? Of course, you will get refund in 2018 and these refund will be added to 2018 income, but 2018 tax rate is lower. So you gain.
I suppose today you can pay 2017 tax directly on state's web site.
I know you cannot prepay 2018 state tax return. But I am asking about overpaying 2017 state tax.
I also know you cannot overpay too much, because if you take too much itemized deduction, AMT get kicked in, and you lose the itemized deduction.
Thanks.
