Rent vs. buy: the math behind the biggest financial decision
Key takeaways
04 · ideas- The 'price-to-rent ratio' in a city predicts buying vs. renting advantage
- The break-even point for buying is typically 5-7 years of staying
- Opportunity cost of the down payment is the most overlooked factor
- Home appreciation of 3% vs. 5% changes the outcome by hundreds of thousands
Basic level
The essentials · 1 min
Buying a home builds equity and provides stability. Renting offers flexibility and lower upfront costs. The question isn't which is "better" — it's which is better for your situation, in your city, at this time.
Three questions determine the answer:
- How long will you stay? Less than 3 years: rent. 7+ years: usually buy. 3–7 years: calculate carefully.
- What's the price-to-rent ratio in your city? Take home price ÷ annual rent. Below 15: buying is favorable. Above 20: renting often wins.
- What would you do with the down payment instead? A $60,000 down payment invested at 7% becomes $118,000 in 10 years. That opportunity cost must be counted.
- Austin: 28 (rent is better at current prices)
- Miami: 26
- New York: 30
- Midwest cities: 12–16 (buying is favorable)
- National average: ~22
Intermediate level
How it applies · 2 min
The full cost model of homeownership
Most people compare mortgage payment vs. rent. The real comparison includes:
Monthly cost of owning $400,000 home (20% down, 6.5%, 30yr):
| Cost | Monthly |
|---|---|
| Mortgage P&I | $2,020 |
| Property tax (1.2%) | $400 |
| Insurance | $150 |
| Maintenance (1% annual) | $333 |
| HOA (if applicable) | $0–$400 |
| **True monthly cost** | **$2,903** |
| − Tax deduction benefit | −$300 |
| **After-tax cost** | **$2,603** |
Monthly rent for comparable unit: $2,200
Renting appears cheaper by $400/month. But ownership builds equity through:- Principal paydown: ~$500/month in early years (growing each year)
- Appreciation: $400,000 × 3% ÷ 12 = $1,000/month
Net equity build: $1,500/month
Adjusted comparison: $2,603 (own) − $1,500 (equity) = $1,103 effective cost vs. $2,200 rent
Homeowner wins by ~$1,100/month — after 5 years.
The 5 and 10 year comparison
$400,000 home, 6.5% mortgage, 3.5% appreciation, renting $2,200/month with 3% annual increase:
After 5 years:- Home value: $473,000
- Remaining mortgage: $345,000
- Equity: $128,000 (vs. $80,000 down payment invested → $112,000 at 7%)
- Ownership net worth advantage: $16,000
- Home value: $560,000
- Remaining mortgage: $301,000
- Equity: $259,000 (vs. $80,000 invested → $157,000)
- Ownership net worth advantage: $102,000
Advanced level
The math, step by step · 2 min
The price-to-rent ratio and expected return
Let P = home price, R = annual rent, g_p = annual price appreciation, g_r = annual rent increase, r_m = mortgage rate, dp = down payment fraction.
Rental yield: R/P — the "dividend" from owning. Higher is better for buyers.
Total return to homeowner:
Where costs = property tax + insurance + maintenance − tax savings ≈ 3–4% of value annually.
For buying to beat renting, we need:
Where r_{invest} = investment return on alternative deployment of down payment.
Solving for the break-even price-to-rent ratio:
At g_p = 3\%, r_{invest} = 7\%, T_g = 15\%:
Below a P/R ratio of 15.5, buying is mathematically superior to investing the down payment and renting. Above 20, renting and investing almost always wins — explaining why expensive coastal cities show renting as the "rational" choice despite strong cultural pressure to buy.
The New York Times Buy vs. Rent Calculator uses a similar model but adds local property taxes, mortgage interest deduction (if applicable), and specific local appreciation rates. For precise local analysis, tools with local data outperform generalized models.