How the mortgagereversal.co calculator works

mortgagereversal.co publishes one tool and a stack of guides that describe what the tool does. This page is the source-of-record for the math: the formula, the federal data sources and the assumptions behind them, and what the calculator deliberately does not estimate. Every number elsewhere on the site traces back here.

What does the calculator do?

The calculator estimates the principal limit for a Home Equity Conversion Mortgage (HECM), the FHA-insured reverse mortgage that accounts for the large majority of reverse mortgages originated in the United States. The principal limit is the most a HECM borrower can draw against the home over the life of the loan, before any payouts, closing costs, or mortgage insurance premiums are subtracted.

Two inputs determine the principal limit: the age of the youngest borrower (or non-borrowing spouse, where applicable) and the maximum claim amount, which is the lesser of the appraised home value and the FHA HECM lending limit. The calculator reads the borrower's age and home value, applies the federal lending limit, looks up the corresponding principal limit factor (PLF) on the HUD-published PLF table for the current expected rate, and returns:

principal limit = maximum claim amount × PLF

The output is an estimate. Estimate·how this number is calculated No part of the calculation collects, transmits, or stores personally identifiable information. Inputs stay in the browser.

The PLF table and the 3.0% expected-rate floor

The principal limit factor is published by HUD as a lookup table indexed by age (18 to 99, in one-year increments; HECM eligibility begins at age 62) and expected rate (in 0.125% increments). Each cell returns a decimal between roughly 0.20 and 0.75, the share of the maximum claim amount that the borrower is eligible to access. HUD hosts the current PLF tables at hud.gov/program_offices/housing/sfh/hecm/rmtopten and the calculator pulls the file at build time so the math reflects the table HUD has live.

The expected rate is the sum of the lender's margin and the 10-year Constant Maturity Treasury (10Y CMT), which the Federal Reserve publishes daily on the H.15 Selected Interest Rates release (FRED series DGS10). HUD's PLF table treats any expected rate below 3.0% as if it were 3.0%, holding the principal limit constant in that zone. The floor was lowered from 5.0% to 3.0% in the rebuilt PLF tables issued under HUD Mortgagee Letter 2017-12, which restructured the HECM principal-limit framework. As of the May 15, 2026 H.15 release, 10Y CMT was 4.59%; combined with typical HECM margins (currently in the 1.75% to 3.25% range based on lender rate disclosures), the expected rate has sat above the 3.0% floor for the entire 2024–2026 period, so the floor is currently non-binding. It will bind again if Treasury yields fall significantly.

What this means in practice: when 10Y CMT moves, the PLF table cell the calculator reads changes, and the principal-limit estimate moves with it. A borrower modeling the same age and home value at a 4.0% expected rate and a 6.0% expected rate will see different numbers. The calculator prints the expected rate it used directly under the result so the assumption is visible.

The FHA HECM lending limit and case-number-year branching

The maximum claim amount is capped at the FHA HECM lending limit, set by HUD each calendar year. The current limit is $1,249,125 for FHA case numbers assigned on or after January 1, 2026, set by HUD Mortgagee Letter 2025-22. The 2025 limit was $1,209,750. A borrower whose case number was assigned in 2025 calculates against the 2025 figure; a borrower whose case number is assigned in 2026 calculates against the 2026 figure.

The calculator defaults to the 2026 limit. For 2025-case-number borrowers, the HECM-mode variant at /calculator/hecm includes a case-number-year toggle so the older limit can be applied. The limit is a federal ceiling on the maximum claim amount, not on the home value itself. A $2.5 million home and a $1.5 million home both produce the same maximum claim amount under HECM, because both are capped at $1,249,125.

Jumbo and proprietary programs: why this calculator returns a range, not a number

Three jumbo (proprietary, non-FHA) reverse-mortgage programs are currently active in the United States: HomeSafe (Finance of America), Platinum Preserve (Longbridge), and SecureEquity+ (Mutual of Omaha Reverse). All three have a minimum borrower age of 55, with state exceptions raising the floor to 60 in Massachusetts, New York, and Washington, and 62 in North Carolina and Texas (HomeSafe). All three publish a maximum loan amount of $4 million. This is a cap on the loan, not on the property value, so a home worth more than $4 million can still qualify; the loan itself is the ceiling.

What none of the three publishes is a rate sheet or a principal-limit table. Proprietary reverse-mortgage parameters are set by each lender and are not anchored to a federal authority. Every public-facing quote for a jumbo principal limit on the open web — including the illustrative LTV curves competitors publish — derives from a non-authoritative reconstruction, and the three live lenders' actual numbers disagree with those reconstructions in the directional cases that can be checked.

For this reason, the calculator's jumbo mode does not output a point estimate. It returns a bounded range drawn from the published parameter ranges of HomeSafe, Platinum Preserve, and SecureEquity+ as of the date each lender's rate sheet was last verified. The range is rendered as {low, high, source, lastVerified} in the output panel, with the source citing the three lender parameter sets and the verification date. A borrower whose home value or age makes a jumbo program relevant should treat the range as a starting point and request a lender quote for a binding number.

Lender parameter inputs are committed to inputs/rates/lender-rates.json and verified weekly. The provenance line under the jumbo range names which parameter sheets fed the calculation and when each was last checked.

What this calculator does not estimate

The principal limit is the starting figure, not the cash a borrower receives. Several deductions and exclusions sit between the principal limit and the disbursement:

• Closing costs vary by lender and by state and are not modeled here. The calculator does not estimate origination fees, third-party closing costs, recording fees, or state-specific taxes.
• Mortgage insurance premium (MIP) is an FHA charge on HECM loans, currently 2.0% of the maximum claim amount upfront plus 0.5% of the outstanding balance annually. The calculator's HECM mode does not subtract MIP from the principal-limit estimate; MIP becomes part of the loan balance over time, modeled in the amortization variant at /calculator/amortization.
• Lender margins above the typical range can change the expected rate enough to move the PLF cell the calculator reads. The calculator uses the current published margin range; a lender quote with an atypical margin will produce a different number.
• Property taxes, homeowner's insurance, and flood insurance remain the borrower's obligation under any HECM and are not modeled. Default on these obligations is grounds for foreclosure under HUD's HECM rules and is the single most common cause of HECM termination outside of borrower death or move-out.
• Individual lender adjustments to the published parameters, including loan-to-value carve-outs in specific states or for specific property types, are not modeled. The calculator treats the published parameters as the input set.

The calculator answers the question, "given my age, my home value, and the current expected rate, what is the maximum the federal program would let me borrow against this home?" It does not answer, "how much cash will a lender wire me at closing." That number requires a lender quote.

Where the data lives and when it refreshes

| Data | Source | Refresh cadence | |---|---|---| | HECM PLF table | HUD, hud.gov/program_offices/housing/sfh/hecm/rmtopten | Pulled at build; HUD updates infrequently | | 10Y CMT | Federal Reserve H.15 release / FRED series DGS10 | Daily, via ISR revalidation | | FHA HECM lending limit | HUD Mortgagee Letter 2025-22 | Annual; next change effective for FHA case numbers on or after Jan 1, 2027 | | Jumbo program parameters | inputs/rates/lender-rates.json (HomeSafe, Platinum Preserve, SecureEquity+ rate sheets) | Weekly, manually verified | | Federal/state rule citations | HUD Mortgagee Letters, FHA Handbook 4000.1, CFPB consumer guidance, state DOI | As issued |

When any of these change, the affected pages rebuild. The <LastUpdated /> stamp on each page reflects the most recent rebuild against current sources.

How the PLF table is sourced and verified

The principal limit factor table this site uses is the HUD HECM Principal Limit Factor table from the file "FY 2018 PLF Tables-Rvsd Introduction.xls", the edition effective for FHA case numbers assigned on or after October 2, 2017 under Mortgagee Letter 2017-12. HUD links the file from its HECM statistics page at hud.gov/stat/sfh/hecm. The table covers borrower ages 62 to 99 in one-year steps and expected rates from 3.0% to 18.875% in 0.125% increments.

The table is committed into the repository at inputs/plf-table.json rather than fetched at request time, so the math is reproducible: the exact factors that produced any published estimate are the factors in version control on the day of the build. The file carries its own provenance metadata — the HUD source description, the table edition, and the date the table was last verified against HUD's published file.

A build-time integrity script, verify-inputs, checks the table before any page is generated. It confirms the rate keys are strictly ascending, every rate row has exactly one factor per age, and every factor falls in the expected open interval between 0 and 1. It also checks two monotonicity rules the HUD table must obey: the factor rises with the age of the youngest borrower, and the factor falls as the expected rate rises, with the 3.0% floor row holding the per-age maximum. If any check fails, the build stops rather than shipping a page built on a malformed table. This is the provenance anchor for every dollar figure on the site, including the per-age estimates on the principal limit pages: each of those traces through lib/plf.ts to this one verified table.

Last reviewed 2026-05-22