If I am300$ over $10000 deduction. Do we take standard deduction of $24000?

[bgwerffeli]

or prepay homemortgage and state taxes this year?

[DoninGA]

You cannot deduct prepaid 2018 state income taxes on a 2017 tax return.
The standard deduction increases are only starting on the 2018 tax year returns, not for 2017

[SweetieJean · Accepted solution]

No. That is effective for 2018 tax returns filed in 2019, not the 2017 ones we are doing now.

https://www.cnbc.com/2017/12/18/prepaying-2018-state-income-taxes-is-blocked-in-gop-bill.html

https://www.irs.gov/newsroom/irs-advisory-prepaid-real-property-taxes-may-be-deductible-in-2017-if-a...

but it may be too late, as municipal tax offices are likely closed for the rest of the year, as is the postal service.

[Critter]

You can prepay some or all of the RE taxes in 2017 by midnight tomorrow  but you cannot prepay state taxes. 

And if your total itemized deductions in 2018 will not be more than the standard of $24K then you will not itemize deductions. 

[fanfare]

Better hope your tax office has a drop box standing outside the door.

[SweetieJean]

With a video camera and clock to prove when you dropped it in!