Home Affordability SimulatorBuy the house without giving up early retirement

The true monthly cost of owning a home

Every mortgage calculator on the internet will tell you the payment. Almost none of them will tell you the bill. The gap between the two is where budgets quietly break: property tax that scales with the home's value forever, insurance that has been repricing upward across most of the country, maintenance that runs on the house's schedule rather than yours, PMI if you put down less than 20%, and — the piece renters systematically underweight — the fact that every one of those keeps growing after the fixed payment stops being the story. Here is the full arithmetic at three price points, using this site's standard cost model (1.1% of value in property tax, 1% in maintenance, insurance indexed to home value):

Payment vs. bill

The overhead is remarkably consistent — roughly 41% to 49% on top of the payment across the whole price range — because its biggest components are percentages of the home's value, just like the mortgage. That gives you a serviceable rule for listings: the real monthly cost is the calculator's payment times roughly 1.4 — more if you're under 20% down (PMI at 0.5% of the loan per year in this model) or in a high-tax county, plus HOA where it applies. On the $500K home, budgeting the payment instead of the bill means planning around $2,463 while actually signing up for $3,538 — a $1,075/mo hole that arrives the first month and never leaves.

Why the gap matters more than it looks

A gap that size sounds absorbable until you follow where it comes from: the money that was supposed to be invested. The overhead doesn't just raise the cost of shelter — it lowers the savings rate that has to outrun the mortgage for the purchase to leave retirement intact, every month, for decades. That compounding leak is exactly what a payment-only calculator can't price and the simulation can: it's a large part of why the odds columns on this site's price-and-salary pages come out more conservative than the 28%-rule tables, and it's the opening chapter of what "house poor" actually looks like. The failure mode isn't drama; it's a portfolio that just… stops growing.

The all-in number is also the right denominator for your emergency fund — a "month of expenses" after closing means a month of this bill plus living costs, not a month of your old rent (sized properly here). Before you commit to a price, run it through the simulator: it carries every line of the bill — growing with inflation and home value, PMI until equity releases it — through thousands of futures, and tells you whether the house fits the life, not just the paycheck.

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