Deductions & credits

If you are taking the standard deduction, your excess property tax is your total property tax, as mentioned by @PaulaM .

You will see a reference to this in TurboTax:

If you itemized your deductions, the excess property taxes would be the taxes not allowable for itemized deductions because of limits applied on the deduction of state taxes. On Form 8829, your property taxes are entered on line 17 only if you take the standard deduction. If you itemize your deductions, the property taxes will show on line 11 for the amount allowable for itemized deductions and the excess on line 17. Either way, all of your property taxes are listed on Form 8829 to be allocated to your home office based on the size of the office to the size of the whole house.