Every conversation about renting versus buying I've had in the last three years runs into the same problem: someone heard a rule of thumb (“rent is throwing money away” / “buy when it's cheaper than renting”) and everyone else has heard a different rule of thumb. The rules contradict each other. They're both wrong, in different ways, in different markets. The actual answer requires running the numbers for your specific situation, and it changes a lot depending on a few inputs that most rules of thumb don't mention.
I've done this calculation for myself three times — once when I rented in a high-cost-of-living market and the math said keep renting, once when I bought in a smaller metro and the math said buy, and once when I almost bought in a third market and the math said don't. Each time the result depended on the same handful of variables. This guide walks through them with worked examples so you can do your own.
The right framework: full all-in monthly cost on both sides
The naive comparison is “monthly mortgage payment vs monthly rent.” It almost always favors buying because it leaves out the costs that don't show up in the mortgage payment. The honest comparison includes everything:
True monthly cost of owning:
- Mortgage principal + interest (P&I)
- Property tax (annual, divided by 12)
- Homeowners insurance
- HOA dues, if any
- PMI, if down payment was less than 20%
- Maintenance and repairs (rule of thumb: 1% of home value per year — $3,300/mo on a $400K house, or roughly $275/month spread out, but lumpy in practice)
- Opportunity cost on the down payment (what that money would have earned elsewhere — often the largest hidden cost)
True monthly cost of renting:
- Rent
- Renter's insurance
- Any utilities not included that would've been included in ownership
And on the rental side, the savings versus buying — the down payment + closing costs you didn't spend, plus the monthly difference between owning and renting — should be invested. The right comparison is total wealth at horizon in scenario A versus scenario B, not just monthly costs.
A worked example
Say you're looking at a $400,000 home in a metro where comparable rentals run $2,400/month. You have $80,000 saved. The mortgage rate is 6.75%. Property tax is 1.2%, insurance is $1,800/year, no HOA. Your alternative use of cash is investing in a diversified equity portfolio with an 8% expected return.
Owning math (year 1):
- 20% down: $80,000 down. Mortgage: $320,000 at 6.75% over 30 years.
- Monthly P&I: ~$2,075
- Monthly property tax: ~$400
- Monthly insurance: ~$150
- Monthly maintenance allowance: ~$333
- Closing costs (one-time): ~$8,000
- Total monthly out-of-pocket: ~$2,958
- Of the $2,075 P&I, only ~$310 is principal in year 1; the rest is interest.
Renting math (year 1):
- Rent: $2,400/mo
- Renter's insurance: ~$15/mo
- Total monthly: $2,415
- You have $80,000 + $8,000 = $88,000 you didn't put into the house. At 8% that's $7,040 of expected first-year growth — call it $587/month.
- You also save $543/month versus buying. Investing that at 8% adds another ~$45/month of first-year growth.
The naive picture says buying is “$2,075 mortgage vs $2,400 rent — buying wins by $325.” The honest picture: buying costs you $2,958 in cash, renting costs you $2,415, and the renter is also growing $88K of capital at 8%. In year one, the renter is meaningfully ahead.
But — and this is the part rules of thumb miss — buying compounds in the other direction over time. Mortgage payments stay flat (in nominal terms) while rents rise. Principal builds equity. Property values appreciate (long-run US average ~3%/year, varies massively by metro). After enough years, the buyer crosses over the renter. The question is when.
The breakeven horizon
For most US markets in 2026, the breakeven for buying tends to land between 5 and 9 years, depending on:
- Local price-to-rent ratio. If a $400K house rents for $3,000, buying breaks even fast (price-to-rent ~11). If it rents for $1,800, buying may never beat renting in plausible time horizons (price-to-rent ~18).
- Mortgage rate. At 4% rates buying breaks even quickly. At 7%+ rates the breakeven stretches to 8–10 years in most markets.
- Expected appreciation. 5%/year appreciation makes breakeven fast. 1%/year (or worse, decline) pushes breakeven indefinitely.
- Opportunity cost.The higher the return on alternative investments, the worse buying looks. This is why buying looked so good in the 2010s with 3% mortgage rates and 8%+ stock returns — the down payment's opportunity cost was overwhelmed by the leveraged appreciation on the home. At higher rates, the math is much closer.
- Tax treatment.Mortgage interest deduction matters less than it used to (TCJA raised the standard deduction). For many middle-class buyers, itemized deductions don't exceed the standard, so the mortgage interest produces no tax benefit.
The transaction-cost reality
Buying and selling a house has serious friction:
- Closing costs (buyer): 2–5% of price. Includes loan origination, title insurance, escrow, appraisal, taxes.
- Closing costs (seller): 6–8% of price, dominated by agent commissions (5–6%) plus transfer taxes and title.
Round-trip, expect 8–12% of the home's value to evaporate in transaction costs. On a $400K house that's $32,000–$48,000. If you buy, sell within two years, and don't see at least that much appreciation, you're simply paying the real estate industry to move you. This is why the standard advice is “don't buy if you might leave within 5 years” — at shorter horizons, you almost certainly lose to renting.
The non-financial factors that matter
The financial math is one half of the decision. The other half is the things money can't price exactly:
- Stability.Owning protects you from rent increases and forced moves. If a stable address matters for kids' schools, aging parents nearby, or a job that requires being in one metro, that has real value.
- Flexibility cost. Selling a house in a hurry is expensive, especially if the market turns. Renting is liquid: notice, move out, done. For a career that might involve relocation, the flexibility premium is real.
- Customization.Owners can renovate, paint, install solar, own pets without negotiation. Renters can't. If you want to make a place yours, ownership has emotional return that doesn't show up in spreadsheets.
- Maintenance burden.When the water heater fails, the renter calls the landlord and gets it replaced. The owner spends a Saturday researching plumbers. The dollar cost is similar; the time and stress cost isn't.
- Forced savings.Most Americans don't actually invest the difference between renting and buying. The mortgage acts as a forced savings program. If you'd otherwise spend the “rent savings,” ownership tilts your behavior toward saving in a way renting doesn't.
How I think about it for myself
Three filters I run before I take buying seriously:
- Will I be in this metro for at least 5 years?If I can't answer yes with high confidence, I'm renting. Transaction costs eat everything below that horizon.
- Is the price-to-rent ratio under 18 in this market? Above 18, the math has to work very hard for buying to beat renting + investing. Below 12, buying is usually clearly correct.
- Can I afford the all-in PITI + maintenance at 28% of gross income or below?If the all-in monthly cost crowds my budget, the house is too expensive — even if I “qualify” for the mortgage. Banks will lend you up to 36–43% DTI. That's not a recommendation; that's a maximum.
If all three pass, I run the actual buy-vs-rent calculator with my expected assumptions, then with stressed assumptions (lower appreciation, higher maintenance, lower investment return on the alternative). If buying still wins under stressed assumptions over my expected horizon, I take the decision seriously.
Common mistakes
- Comparing only mortgage payment to rent. This always favors buying and is usually wrong.
- Ignoring opportunity cost on the down payment. An $80K down payment foregone from an 8% portfolio costs $6,400 in expected returns the first year alone.
- Assuming home appreciation will continue at recent rates.In some metros 2020–2022 saw 30–50% price appreciation. The historical norm is 3–4% nominal. Projections that assume the recent past as base case will almost always favor buying. Use long-run averages instead.
- Forgetting maintenance. Owners systematically underestimate this. The 1%-of-home-value rule is a reasonable starting point and reality tends to come in slightly above for older homes, slightly below for new construction.
- Treating “equity” as if it's liquid.Home equity is real, but it's expensive to access (HELOC interest, refi costs, or full sale with 8% transaction friction). Don't treat it as a cash equivalent.
Tools that help
- Mortgage calculator — get your true PITI for any home price, rate, and down payment
- Down payment calculator — model the trade-off between higher down payment and higher monthly investing
- Investment calculator — model what the down payment would have grown to if invested instead
- Cost of living comparison — compare metros for rents and home prices
Final thought
Owning a home isn't a financial slam-dunk and it isn't a financial mistake. It's a leveraged bet on a single asset in a single metro, evaluated against the alternative of renting and investing the difference. In some markets, at some rates, with some horizons, buying is clearly correct. In others, renting is. The honest answer is “run the numbers for your situation, then decide what trade-offs you can live with.” The rules of thumb that say one always beats the other are wrong because they pretend a multi-variable question has a one-variable answer.