The new tax bill that takes effect in 2018 raises the standard deduction and caps certain itemized deductions. Therefore, if you will itemize your deduction in 2017, you may want to grab whatever you can this year to get the full value of those deductions. (This assumes you are not subject to AMT.) Here’s a brief summary of your options.
- State and Local Income Taxes. You can’t prepay 2018 state taxes in 2017. However, you should pay all your 2017 taxes in 2017. Specifically, if you make estimated quarterly tax payments, you should makes your 4th Quarter state/local payment by December 31, 2017 rather than wait until the deadline which is usually close to the federal deadline of January 18, 2018.
- Property Taxes. You can’t prepay 2018 property taxes in 2017. However, if you have property taxes based on 2017 assessments (partial or whole), you should make those payments by December 31, 2017. Basically, have you received a bill already? Pay it now. Some counties are actually trying to make things easier for you. See these NYT and WaPo articles for details. Things can get complicated if you usually pay via mortgage escrow.
- Charitable contributions. On a related note, you may want to make your charitable contributions by the end of 2017, as you may not be able to deduct your donations if you will fall under the standard deduction in 2018.