Mortgage Cancellation Relief Act of 2012 - Amends the Internal Revenue Code to allow a permanent exclusion from gross income of amounts attributable to the discharge of qualified residential indebtedness, in the case of an individual (currently, limited to principal residence indebtedness discharged before January 1, 2013).
Defines "qualified residential indebtedness" to mean indebtedness, including indebtedness from refinancing, that was incurred or assumed: (1) in connection with real property used as a residence and that is secured by such real property; and (2) to acquire, construct, reconstruct, or substantially improve such property.
Limits the amount of such exclusion to the excess (if any) of the outstanding principal amount of such indebtedness (immediately before the discharge) over the sum of: (1) the amount realized from the sale of such real property reduced by the cost of the sale, and (2) the outstanding principal amount of any other indebtedness secured by such property.