compare_rent_vs_buy

ai.senaro/personal-finance · Verify this server

Calculation, not advice. Verify with a professional before acting. Deterministic rent-vs-buy decision model. Given a home price, monthly rent, and mortgage rate, computes the breakeven month (when BUY net worth first equals or exceeds RENT net worth), per-horizon net-worth comparison (years 5, 10, 30 + user horizon), and the full year-by-year cost/wealth series for both paths. Includes carrying costs (property tax, insurance, maintenance, PMI, HOA) on the BUY path and opportunity-cost investing on the RENT path. Optional federal tax benefit model (Tier-3: apply_tax_benefit=true) with the statute's year-by-year SALT cap schedule (advancing with the horizon, not frozen at tax_year), mortgage interest deduction, PMI deductibility, and marginal-excess formula. All assumptions cite primary sources (FHFA, BLS, Harvard JCHS, IRS Pub 936, OBBBA Pub. L. 119-21) and can be overridden. Pick this for the buy-vs-rent tenure decision; pick `compare_mortgage_terms` when you are already buying and comparing two mortgage structures, `compare_payoff_strategies` to order credit-card payoff, and `compare_payoff_vs_invest` to weigh extra debt payments against investing. HEAVY tool: use output='summary' (default) for scalar headline or output='inline' for chart series.