That is an itemized deduction. Itemized deductions provide no tax benefit until all of them added together are more than your standard deduction.
2016 Standard Deduction
Taxpayer under 65, not claimed as a dependent
$6,300 for Single
$12,600 for Married Filing Jointly, or Qualifying Widow(er) with dependent child
$9,300 for Head of Household
$6,300 for Married Filing Separately
For over 65 or blind, add $1,250 for each instance or add
$1,550 each instance if single and not a surviving spouse.
Once your total itemized donations are more than your standard deduction, each additional dollar of deductions reduces your tax by the dollar times your marginal tax rate. For example, if you are in the 25% marginal tax rate bracket each additional dollar of deductions reduces your tax by a maximum of 25 cents.