Enter your deductions, and if the total is such that the amount of allowed itemized deductions are greater than the standard deduction, Turbotax will automatically switch over to itemized deductions.  Remember that itemized deductions do not count 1 for 1 as a reduction in income.  For example, only medical expenses in excess of 7.5% of your AGI count toward the itemized deduction.  Furthermore, there is a $10,000 limit on state and local taxes, including property tax.