The size of the loan is generally determined by a combination of factors including the homeowners' age, the available interest rate, and the value of their home. As a rule of thumb, the older they are, the larger a percentage of the home's value they can borrow. One important restriction for government-insured loans: A reverse mortgage amount is capped by the maximum Federal Housing Administration (FHA) mortgage limit for the area, which maxes out at $160,950. So homeowners in more expensive areas can't borrow as high a percentage of their total home equity as owners in less expensive areas.