The Argument We Have Had Three Times
My wife and I bought our house in 2019. We have had the rent-versus-buy argument — not with each other, but internally, each of us separately — approximately three times since then, triggered by different moments: once when a large repair bill arrived unexpectedly, once when we watched friends in a different city rent a significantly nicer apartment than we could afford to buy in our market, and once when I spent a Saturday afternoon doing yard work I did not want to do and found myself genuinely envious of our renter friends who called their landlord for everything.
I am writing this not as someone who regrets buying, but as someone who actually ran the numbers before buying and wants to share what that analysis looked like honestly — including the parts where the math did not point clearly in either direction.
The Setup: What We Were Actually Comparing
In 2019, we were choosing between two options:
Option A: Buy. Purchase a house at $385,000, put 10% down ($38,500), take a 30-year mortgage at 3.85% on the remaining $346,500. Monthly mortgage payment: approximately $1,624. Property taxes: approximately $420/month. Homeowner's insurance: approximately $140/month. Estimated maintenance and repairs (the oft-cited 1% of home value per year): approximately $320/month. Total monthly housing cost: approximately $2,504.
Option B: Rent. Rent a comparable home in the same neighborhood for $1,950/month, investing the difference between the rent and the ownership cost plus the down payment in index funds.
The monthly difference: $2,504 (own) versus $1,950 (rent) = $554/month more to own. Plus the $38,500 down payment that could remain invested if we rented.
The Compound Interest Math on the Investment Side
This is where renting looks more attractive than most homebuying advocates acknowledge. If we had rented and invested the $554 monthly difference plus kept the $38,500 down payment in a diversified index fund at 7% annual return for 30 years:
- $38,500 invested at year zero, 30 years at 7%: grows to approximately $292,000
- $554/month invested for 30 years at 7%: grows to approximately $668,000
- Total investment portfolio after 30 years: approximately $960,000
That is a real number. Nearly a million dollars in investment wealth from the money we would have otherwise spent on the incremental cost of ownership versus renting. The compound interest calculator makes the renting-and-investing case look genuinely compelling.
The Home Appreciation Side
Now the ownership side of the ledger. Home prices in our area have historically appreciated at roughly 3.5%–4.5% annually over long periods — roughly in line with inflation plus a small premium. Using 4% annual appreciation:
$385,000 home value at 4% appreciation for 30 years: approximately $1,250,000.
Minus the remaining mortgage balance (approximately zero after 30 years, assuming we pay on schedule) = approximately $1,250,000 in home equity.
Versus the renter's investment portfolio: approximately $960,000.
Ownership appears to win by approximately $290,000 at the 30-year mark, under these assumptions.
But the assumptions matter enormously. If home appreciation averages 3% instead of 4%, the home is worth approximately $934,000 at year 30 — and the renter's portfolio wins. If investment returns average 8% instead of 7%, the renter's portfolio grows to approximately $1,170,000 — and renting wins decisively. The outcome is extremely sensitive to two numbers neither of us can predict with confidence over 30 years.
What the Calculator Cannot Model
The rent-versus-buy comparison is the financial analysis I have seen done most incompletely in personal finance content, because the variables that actually determine the outcome for a specific person in a specific city are routinely omitted from the "simple comparison."
Rent inflation. We assumed a fixed $1,950 rent for 30 years in the renting scenario. In reality, rents have inflated at roughly 3%–5% annually in most U.S. markets. At 4% annual rent inflation, that $1,950 becomes $6,320 per month in year 30. The mortgage payment stays at $1,624. The monthly ownership advantage grows dramatically over time as the fixed mortgage payment becomes relatively cheaper while rent escalates. This is one of the most powerful arguments for buying that the simple compound interest comparison misses entirely.
The cost of moving. Renters move more frequently. Each move involves transaction costs, time, disruption, and in tight rental markets, often higher rents in the new unit. The compound interest model treats renting as frictionless. It is not.
Actual maintenance costs. The 1% annual maintenance estimate is a reasonable average, but it smooths over the reality that repairs are lumpy and unpredictable. The year we replaced the furnace ($4,200), the water heater ($1,100), and had a plumbing issue ($800) — all in the same 14 months — our actual maintenance costs were closer to 1.6% of home value. In a bad year, ownership costs significantly more than the model suggests.
The behavioral reality of "investing the difference." The renting-and-investing scenario only works if you actually invest the difference. In practice, many people who rent do not rigorously invest the cost difference between renting and owning — the money diffuses into lifestyle spending. A mortgage is forced savings. The discipline it imposes has real value that does not show up in a compound interest comparison.
What We Actually Think About Our Decision Now
We bought in 2019 at 3.85% and our home has appreciated significantly — probably more than the 4% annual rate I used in the model. On a purely financial basis, buying when we did looks like the right call. But that is partly luck of timing that I would not take credit for as planning.
If we were making the same decision today, with 7% mortgage rates instead of 3.85%, the math would look substantially worse for buying. The monthly cost difference between owning and renting would be much larger, making the investment-opportunity-cost of ownership much higher. At 7%, I am genuinely not sure we would buy — at least not at the same price point.
The honest conclusion from running these numbers carefully is that rent versus buy is not a question with a universal answer. It depends on your local market's price-to-rent ratio, your expected tenure in the home, mortgage rates at the time of purchase, your actual discipline around investing any monthly savings from renting, and how you value the stability and autonomy of ownership versus the flexibility of renting. None of these are small variables.
What the compound interest calculator can do is make the opportunity cost of the down payment and the monthly cost difference concrete and honest. Use our compound interest calculator to model the investment value of your down payment and monthly ownership premium over your expected holding period. Run it at 3%, 4%, and 5% home appreciation assumptions. Run the investment side at 6%, 7%, and 8%. Look at the range of outcomes rather than a single projected number. The answer will probably not be clean. That is because the question is not clean. Anyone who tells you otherwise is simplifying something that deserves more honesty than that.