Where the numbers come from — and when they were last touched.

AUGUST 2026

Mortgage-insurance deduction corrected. If you put less than 20% down and your income falls between $100,000 and $109,000, the deduction phases out — but we were phasing it out twice as fast as the law does. A single filer at $103,000 was shown 40% of the deduction where the law allows 70%, and above $105,000 we had already zeroed it while the page described a range topping out at $110,000 — which was itself wrong, since ten steps exhaust the deduction at $109,000. The phase-out now follows the statute ($1,000 steps, or $500 filing separately, rounded up), and the note on the Tax tab names the range for your own filing status instead of quoting the joint one to everybody.

AUGUST 2026

Verification widened beyond the fixed-rate core. Refinancing, adjustable rates, the tax chain, the renter’s investment portfolio, the break-even month, capital gains at sale, and all eighteen free tools are each now checked by methods that do not reuse the engine’s own arithmetic — closed-form algebra, exact integer-cent arithmetic, published rules transcribed into tables, and laws relating one run to another. Each of those checks was itself tested by deliberately breaking the code to confirm it fails: 34 injected defects, including the two refinance bugs that really shipped, all caught.

AUGUST 2026

Cost tables reconciled column by column. Your down payment and closing costs now appear under Buy Gross as well as Buy Net — previously they were counted only in the net column, which made the gross total come out smaller than the net total. A new audit now checks every total against its own column on every table we publish, in the app and in the report, and fails the build if one drifts.

AUGUST 2026

Cost timing corrected across the engine. Rent now steps once a year at lease renewal rather than compounding every month, and property tax, maintenance and insurance are reassessed annually against the home’s projected value instead of being fixed at the purchase price. Every month inside a given year now carries the same figure, so yearly totals equal the months that make them up.

AUGUST 2026

Tax-benefit timing made truthful. A year’s mortgage-interest and property-tax deductions are claimed when you file, so the engine now credits them from the following January instead of the same month. Year 1 shows the full cost of owning and the savings appear from Year 2 — which also removed a jump that appeared mid-way through later years. The annual cost tables now state this timing directly, including the final year’s deduction, which you claim the April after the table ends.

AUGUST 2026

Refinance modelling fixed. Cash-out proceeds are now credited to your cash flow (previously the loan grew but the money went uncounted), and a refinance scheduled after the loan is already paid off reports nothing instead of inventing savings. Adjustable-rate schedules were corrected start to finish.

AUGUST 2026

Every figure above is now guarded by a permanent audit that recomputes the engine independently across 1,505 scenarios — boundaries, randomised sweeps, ARM and refinance reference implementations — and runs before any change ships.

AUGUST 2026

Q+ AI assistant added — answers questions about your own results and turns plain-English what-ifs into real engine runs. It only restates figures the engine computed; it never calculates. FHFA appreciation data added to this page: it was already powering ZIP-based appreciation suggestions but had been omitted from the source list above.

JULY 2026

Landing page rebuilt — every city verdict and chart number on it is computed by the same engine the calculator uses, from published metro medians (June 2026 snapshot). Sample Q+ report published.

MARCH 2026

Market report data snapshot — Zillow ZORI rents, Census ACS property taxes, and FRED rate data refreshed across all 13 metro reports.

FEBRUARY 2026

Article library first published — metro reports and strategy guides, each with sources cited.