Sales tax that you paid on purchases during the year is all deductible, or you can use the full estimated amount from the IRS tables. However . . .
1. You can deduct either sales tax or state and local income tax, but not both. You would choose whichever is higher.
2. Sales tax is an itemized deduction. The deduction will not make any difference in your tax unless your total itemized deductions are more than your standard deduction.
3. Under the new tax law, for 2018 through 2025, the total deduction for state and local taxes is limited to a maximum of $10,000 per year ($5,000 if you are married filing separately). The maximum applies to the total of real estate tax, personal property tax, and either state and local income tax or state and local sales tax.