Your mileage calculation is included in Employment Expenses which are considered part of Miscellaneous Itemized Deductions. It is not a tax credit.
The total of all Miscellaneous Itemized Deductions must be more than 2% of adjusted gross income to be included in the calculation of itemized deductions.
Itemized deductions are used to lower your taxable income only after the total of your itemized deductions is more than the standard deduction.
The standard deduction is the amount the IRS allows everyone to deduct from their income, so that everyone has at least some income that is not subject to income tax. The amount of the standard deduction depends on what filing status you use.
For 2016 the standard deduction amounts are:
Single 6,300 + 1,550 for 65 and over
HOH 9,300 + 1,550 for 65 and over
Joint 12,600 + 1,250 for each 65 and over
Married filing Separate 6,300 + 1,250 for 65 and over
What this means is, for example, a single person must have more than $6,300 in itemized deductions before they will see a reduction in their taxes for using itemized deductions.
