Reverse Mortgage Loan Balance Growth Calculator

Understanding the reverse mortgage balance calculator — concept and principle

A reverse mortgage lets older homeowners borrow against their home without making monthly repayments. Instead, interest and insurance charges are added to the loan, so the balance grows over time and is usually repaid when the home is sold. This calculator projects the loan balance after a number of years from a lump sum and any monthly advances, and compares it with the estimated future home value to show the equity left.

How it is calculated

With lump sum P, monthly advance a, loan rate plus annual insurance and fees combined into a monthly rate j = (rate + fees) ÷ 1200, and M months:

• Each month: balance ← balance × (1 + j) + a.
• Home value after the period: H = home value × (1 + growth)^years.
• Cash received = P + a × M; interest and fees accrued = balance − cash received.
• Remaining equity = H − balance; loan-to-value = balance ÷ H.

The principle

Because nothing is repaid, interest is charged on interest every month, so the balance grows exponentially, roughly doubling in about ten years at a combined 7%. The home value also grows, but usually more slowly, so the borrower's equity share shrinks over time. In some programs, such as the US Home Equity Conversion Mortgage, the loan is non-recourse: you or your heirs never owe more than the home is worth when it is sold. Eligibility, payout limits and fees depend on age and national rules.

Worked example

Default inputs: lump sum $100,000, no monthly advance, rate 6.5%, insurance and fees 0.5%, 15 years, home $400,000 growing 3% a year.

1. Monthly rate: (6.5 + 0.5) ÷ 1200 = 0.5833%.
2. Balance after 180 months: 100,000 × 1.005833¹⁸⁰ = $284,895.
3. Interest and fees accrued: 284,895 − 100,000 = $184,895.
4. Home value: 400,000 × 1.03¹⁵ = $623,187.
5. Remaining equity: $338,292; balance ÷ home value 45.7%.

How to read the result

A rising balance-to-value ratio means less is left for you or your heirs. Taking money gradually as monthly advances, or only when needed, keeps the balance lower than a large lump sum. If home prices stagnate, equity disappears faster; try a lower growth rate to see a cautious case.

Common mistakes

• Assuming the balance stays at the amount borrowed.
• Using an optimistic home price growth rate.
• Forgetting upfront costs and ongoing obligations such as property tax, insurance and maintenance.
• Treating the remaining equity as guaranteed.

Frequently asked questions

Can I owe more than my home is worth?

In non-recourse programs such as US HECM loans, repayment is limited to the home's value when sold, but heirs receive less or no equity.

Do I have to make payments?

No monthly loan payments are required, but you must keep paying property taxes, insurance and upkeep.

Is a monthly advance better than a lump sum?

It usually leads to a smaller balance because less money accrues interest early.

Sources: U.S. Department of Housing and Urban Development, Home Equity Conversion Mortgage (HECM) program · Consumer Financial Protection Bureau, reverse mortgage guide