How does the invest-the-difference model work?

Both households pay for housing each month; whoever pays less invests the difference, and the renter also invests the buyer's upfront cash (down payment + closing costs). At the horizon the model compares net worth: the buyer's home equity net of selling costs plus side investments, versus the renter's investment pot.

Why does renting start ahead?

The renter keeps the down payment and buying closing costs invested from day one, while the buyer converts that cash into an illiquid asset and pays transaction costs. Buying catches up as equity builds and rent rises — the crossing year is the model's break-even.

What assumptions matter most?

Ownership costs and the mortgage rate move the answer most, with home appreciation right behind — a single point of yearly ownership costs swings the verdict more than a point of investment return, and none of them are knowable in advance. Time horizon matters too: transaction costs make short stays strongly favor renting almost regardless of the other inputs.

Is 'renting wins' realistic?

Only if the renter actually invests the difference every month instead of spending it. That discipline assumption is the model's weakest link in practice — a mortgage is, among other things, forced savings.

Free calculator · no signup · runs in your browser

Rent vs. Buy Calculator

The honest version of this comparison: buying builds home equity, but renting keeps the down payment invested — plus whatever owning costs above rent each month. This compares net worth on both paths, year by year, and admits when it's too close to call.

Home price

Down payment

Mortgage rate

Monthly rent (comparable home)

Years you'll stay

yrs

Home appreciation

%/yr

Investment return

%/yr

Rent increase

%/yr

Yearly ownership costs (tax, insurance, upkeep)

% of value

Fixed in the model: 30-year loan, 3% buying closing costs, 6% selling costs — the standard round numbers; the in-app version makes them editable.

Verdict

—

Buy net worth

Rent net worth

Buying breaks even

—

The two paths, year by year

Buying (equity + investments) Renting (investments) Break-even — buying catches up

Worth knowing: ownership costs and the mortgage rate move the answer most, with home appreciation right behind — a single point on the yearly-ownership-costs field swings this more than a point of investment return, and none of them are knowable in advance. "Renting wins" only holds if you actually invest the difference every month instead of spending it. The renter's investment pot is counted before taxes here, while home-sale gains are largely tax-free — a real-world edge for buying this page doesn't price. And the model can't price the non-financial side: the stability of owning vs. the flexibility of renting.

Why most rent-vs-buy comparisons are rigged

The version you usually see — "rent is throwing money away, a mortgage builds equity" — quietly deletes the renter's biggest asset: the down payment they never spent. Put $90,000 down on a house and that cash becomes drywall; keep renting and it stays invested, compounding from day one. Add the costs owning carries that rent doesn't (property tax, insurance, upkeep — often 2–3% of the home's value every year, forever), and the fair comparison is two net worths, not two monthly payments.

That's the model here: both households spend on housing monthly, whoever pays less invests the gap, the renter also invests the buyer's upfront cash, and at your horizon we compare the buyer's equity (net of selling costs) plus side investments against the renter's pot.

How to read the chart

Renting starts ahead — the invested down payment is a head start buying has to run down. Buying gains as the loan amortizes, the home appreciates, and rent inflates upward while the mortgage payment stays flat. Where the lines cross is the break-even year (with some inputs one side stays ahead the whole way — then there's no crossing to find): sell before it and renting won; stay past it and buying pulls away. That's why time-in-the-home dominates this decision — the ~9% round-trip transaction costs need years to amortize.

What actually decides it

Ownership costs and the mortgage rate move the answer most, with home appreciation right behind — a single point on the yearly-ownership-costs field swings this more than a point of investment return. On this page's defaults the verdict leans to renting; push appreciation past about 4¼% and buying takes it — and all of those inputs are within historical experience. Anyone who tells you the answer with certainty is really telling you their forecast. What you can control: how long you stay (longer favors buying), the price-to-rent ratio of your market, and whether you'd genuinely invest the difference.

Common questions

Is rent really "throwing money away"?

No more than mortgage interest, property tax, insurance, and upkeep are — both paths have pure-cost components. Rent buys housing plus flexibility; ownership costs buy housing plus a leveraged asset. The waste framing survives because equity is visible and the renter's invested difference usually isn't.

Doesn't leverage make buying the obvious winner?

Leverage amplifies both directions. 20% down on a home that appreciates 4% is a ~20% return on your cash before costs — but the same leverage magnifies a flat or falling market, and the 2–3%/yr carrying costs apply to the whole home value, not your equity slice. Leverage is why buying can win big, not why it must.

What about the mortgage-interest tax deduction?

Less than it used to be. Since the standard deduction roughly doubled (2018), most homeowners no longer itemize, so the deduction is worth $0 to them. If you do itemize at a high bracket, it nudges the math toward buying — a nudge, not a verdict.

How should I set the rent field?

Use the rent for a home you'd actually accept as an alternative — comparing a 4-bedroom purchase against a 1-bedroom rental smuggles a lifestyle downgrade in as "savings." The comparison is only honest when both paths house you equally well.

Test the purchase against your real plan

Tesserae's What-if sandbox runs "buy a home" against your actual accounts — the cash hit, the monthly change, and what it does to your retirement date. Privacy-first: you enter your own numbers, and we never touch your bank login.

Try Tesserae free for 7 days See what's inside

Rent vs. Buy Calculator

Why most rent-vs-buy comparisons are rigged

How to read the chart

What actually decides it

Common questions

Test the purchase against your real plan

More from Tesserae