IRS Link to Publication — Found Here
Individuals over 65 years old or are disabled may be eligible for a tax credit. Publication 524 describes this credit in detail.
The credit is only available to those whose adjusted gross income (AGI) is relatively low, and the income limits are described in Pub. 524. Individuals over the age of 65 or younger than 65 but permanently disabled may be eligible to receive a federal income tax credit.
In order to be eligible, the individual’s income must be below certain modest limits, as defined in Publication 524. To get the deduction, individuals must use Schedule R from From 1040 or Form 1040A.
In general the credit will be somewhere between $3,750 and $7,500.
Tax credits are applied after a person’s tax rate and payment amount have already been calculated, and they are a dollar-for-dollar reduction of the taxes that would be due. Chapter 33 of Publication 17 and Chapter 5 of Publication 554 can also be used for reference.