What rent makes buying worth it?
At a 6.5% mortgage, buying a $420,000 home beats renting only when a comparable rental costs more than $2,468 a month — about 0.59% of the home's value. Below that threshold, renting and investing the difference builds more wealth over a 10-year stay. The threshold at every rate:
| Mortgage rate | Buying wins above (rent/mo) | As % of home value | As price-to-rent ratio |
|---|---|---|---|
| 4% | $1,890 | 0.45% | 18.5 |
| 4.5% | $2,003 | 0.48% | 17.5 |
| 5% | $2,117 | 0.50% | 16.5 |
| 5.5% | $2,233 | 0.53% | 15.7 |
| 6% | $2,350 | 0.56% | 14.9 |
| 6.5% | $2,468 | 0.59% | 14.2 |
| 7% | $2,587 | 0.62% | 13.5 |
| 7.5% | $2,708 | 0.64% | 12.9 |
| 8% | $2,829 | 0.67% | 12.4 |
Read it as: the cheaper the money, the lower the rent that justifies buying. Each row is a full month-by-month simulation of the default scenario below with only the rate changed.
Who wins the default 2026 scenario?
Renting wins by about $67,000 over 10 years. The scenario: a $420,000 home versus a $2,100 comparable rental, 20% down at 6.5%, both sides investing whatever they don't spend, measured on ending net worth after selling costs and taxes on both sides.
The same scenario at a 4% mortgage flips: buying wins by about $38,000, breaking even in year 6. The rate, not the slogan, decides the answer.
How does the mortgage rate change the answer?
On the default scenario, here is the verdict and the ending net-worth gap at each rate — same home, same rent, same 10-year stay:
| Mortgage rate | Verdict | Net-worth gap after 10 years |
|---|---|---|
| 4% | Buying wins | $38,000 |
| 4.5% | Buying wins | $18,000 |
| 5% | Renting wins | $3,000 |
| 5.5% | Renting wins | $24,000 |
| 6% | Renting wins | $46,000 |
| 6.5% | Renting wins | $67,000 |
| 7% | Renting wins | $89,000 |
| 7.5% | Renting wins | $111,000 |
| 8% | Renting wins | $134,000 |
How long do you have to stay for buying to win?
Longer than most people assume, unless money is cheap. At 6.5%, buying never catches up in the default scenario: renting leads by $49,000 after 5 years, $67,000 after 10, and $389,000 (nominal) after 30. At 4%, buying breaks even in year 6 and leads by $172,000 after 30 years. Over a 30-year stay buying wins at rates up to 4%; over 10 years only up to 4%. Each cell is the verdict and the net-worth gap at the end of the stay:
| Stay | 4% | 5% | 6% | 6.5% | 7% | 8% |
|---|---|---|---|---|---|---|
| 5 yrs | Rent +$2k | Rent +$21k | Rent +$40k | Rent +$49k | Rent +$59k | Rent +$78k |
| 10 yrs | Buy +$38k yr 6 | Rent +$3k | Rent +$46k | Rent +$67k | Rent +$89k | Rent +$134k |
| 15 yrs | Buy +$83k yr 6 | Buy +$13k yr 11 | Rent +$60k | Rent +$97k | Rent +$135k | Rent +$212k |
| 20 yrs | Buy +$124k yr 6 | Buy +$17k yr 11 | Rent +$94k | Rent +$152k | Rent +$211k | Rent +$331k |
| 30 yrs | Buy +$172k yr 6 | Rent +$43k | Rent +$271k | Rent +$389k | Rent +$510k | Rent +$759k |
"Buy +$38k, yr 6" means buying ends the stay $38,000 ahead and first pulls ahead in year 6. Gaps are nominal dollars at the end of the stay, after selling costs and taxes on both sides. The 30-year column runs past the mortgage's payoff, which the engine handles.
Does staying longer lower the rent that justifies buying?
Only modestly. At 6.5% the tipping rent falls from $2,769 for a 5-year stay to $2,375 for 30 years — the rate moves it far more than the horizon does. The rent above which buying wins, by stay and rate:
| Stay | 4% | 5% | 6% | 6.5% | 7% | 8% |
|---|---|---|---|---|---|---|
| 5 yrs | $2,131 | $2,384 | $2,640 | $2,769 | $2,899 | $3,161 |
| 10 yrs | $1,890 | $2,117 | $2,350 | $2,468 | $2,587 | $2,829 |
| 15 yrs | $1,858 | $2,062 | $2,273 | $2,382 | $2,492 | $2,716 |
| 20 yrs | $1,886 | $2,070 | $2,263 | $2,362 | $2,463 | $2,670 |
| 30 yrs | $1,978 | $2,131 | $2,292 | $2,375 | $2,461 | $2,637 |
What assumptions produce these numbers?
Every figure above assumes: $420,000 home price, $2,100 monthly rent, 20% down, a 30-year fixed mortgage, 3% annual home appreciation, 2.5% annual rent growth, 7% nominal investment return, a 10-year stay unless the table says otherwise, US 2026 tax rules with the standard deduction, PMI below 20% equity with automatic termination, and full buying and selling costs. Change any of them for your own case in the calculator — every input is adjustable and every scenario is a shareable URL. For real markets rather than the default scenario, see rent vs. buy across the 97 largest US metros.
Can I download or cite these numbers?
Yes. The full horizon-by-rate matrix is at /numbers.csv (one row per cell) and, with the assumptions and provenance attached, at /numbers.json. Both are regenerated on every deploy. The data is published under CC BY 4.0: reuse it freely, with a link back to this page. A citation that carries what a reader needs:
RentVsBuyMath, "Rent vs. Buy: The Key Numbers," rentvsbuymath.com/numbers, computed October 17, 2026 with the open-source RentVsBuyMath engine. Default scenario: $420,000 home, $2,100 rent, 20% down, 7% investment return.
If you quote one figure, quote its assumptions with it — the numbers are only meaningful as a set.
Where do these numbers come from?
From an open-source simulation engine (MIT-licensed) that models both paths month by month and is covered by 188 automated tests, including 10 verification scenarios computed by hand independently of the code. Every formula is documented on the methodology page. This page renders from that engine at build time — the numbers here cannot disagree with the calculator, because they are the calculator.