The 1% rule is the most quoted piece of advice in rental property investing. It's also mostly useless now.
The rule is simple: monthly rent should equal at least 1% of the purchase price. Buy a $200,000 property, charge $2,000/month, you're good.
Except you're probably not. Here's why the rule died — and what replaced it.
What Killed the 1% Rule
Interest Rates Tripled
The 1% rule made sense when you could get a mortgage at 3.5%. Your debt service was low enough that 1% of purchase price as rent meant actual cash flow.
At 7% rates, the math breaks completely. A $250,000 property at 3.5% costs you $843/month in principal and interest (20% down). At 7%, that same loan costs $1,331/month. That's an extra $488/month in expenses — nearly $6,000/year.
Your 1% rent didn't change. Your mortgage payment went up 58%. The rule stopped working.
Property Taxes and Insurance Exploded
The 1% rule never accounted for regional variance in property taxes. Texas charges 1.8% of assessed value annually. Illinois runs similar. California is capped at 1% but starts from a higher base.
Insurance has gotten worse. Climate risk, replacement cost inflation, and reinsurance chaos have pushed premiums up 30-50% in some markets over the last three years. What used to cost $100/month now costs $150-$200.
The 1% rule assumed stable, predictable expenses. That assumption is gone.
The Markets That Hit 1% Are the Wrong Markets
You can still find properties that hit the 1% rule. They're in Cleveland, Detroit, parts of the rural Midwest. High crime, weak job growth, declining population.
Low prices, yes. But you're not buying cash flow — you're buying risk. Vacancy, tenant quality, maintenance costs, and property value decline all go up when you're chasing the 1% rule in tertiary markets.
The investors who do well in those markets know them intimately. They have local teams. They can manage the risk. If you're reading this article, that's probably not you.
What Actually Works Now
The Debt Service Coverage Ratio (DSCR)
Lenders don't use the 1% rule. They use DSCR: net operating income divided by annual debt service.
If your NOI is $18,000/year and your mortgage costs $15,000/year, your DSCR is 1.2x. Most lenders want to see at least 1.25x. Below 1.0x, you're cash-flow negative.
This is better than the 1% rule because it accounts for actual expenses and actual debt service. It's not a shortcut. It's the real number.
The Expense-to-Income Ratio
Calculate your total operating expenses (taxes, insurance, management, maintenance, CapEx, vacancy) as a percentage of gross rent. If you're above 50%, the deal is tight. Above 60%, it's probably dead.
This forces you to model the actual costs instead of assuming "1% means it works."
The 15% Cash Flow Margin
After all expenses including debt service, you should have at least 15% of gross rent left as cash flow. On a $2,000/month property, that's $300/month or $3,600/year.
If you can't hit that, the deal has no buffer. One bad month, one unexpected repair, and you're writing a check.
A Real Example: 1% Rule vs. Reality
Let's compare two properties, both passing the 1% rule.
Property A: Midwest tertiary market
- Purchase price: $120,000
- Monthly rent: $1,200 (hits 1% rule)
- Mortgage at 7% (20% down): $638/month
- Property taxes: $180/month
- Insurance: $120/month
- Management: $96/month
- Maintenance/CapEx: $180/month
- Vacancy: $72/month
- Total expenses: $1,286/month
- Cash flow: -$86/month
The 1% rule said this works. The actual math says you're losing money every month.
Property B: Sunbelt growth market
- Purchase price: $320,000
- Monthly rent: $2,400 (0.75% — fails 1% rule)
- Mortgage at 7% (25% down): $1,598/month
- Property taxes: $400/month
- Insurance: $180/month
- Management: $192/month
- Maintenance/CapEx: $360/month
- Vacancy: $144/month
- Total expenses: $2,874/month
- Cash flow: -$474/month
This one's even worse. But change the down payment to 35%, and the mortgage drops to $1,367/month. Cash flow becomes -$241. Still negative, but now you're in appreciation-play territory in a strong market.
Neither property is obviously good. The 1% rule told you nothing useful.
What to Do Instead
Stop using shortcuts. Model the actual deal:
- Get real rental comps — not Zestimate guesses
- Calculate actual expenses — use 50% of gross rent as a floor if you don't have specifics
- Model your actual mortgage payment at current rates
- Calculate cash-on-cash return and DSCR
- Stress-test at -15% rent
If it works at -15% rent, it's worth pursuing. If it barely works at asking rent, it doesn't work.
The Honest Truth
Most deals right now don't pencil. Interest rates are high, prices are still elevated, and rents haven't caught up. You're either buying for appreciation in strong markets (and accepting thin or negative cash flow), or you're sitting on the sidelines.
The 1% rule can't tell you which strategy makes sense. Actual underwriting can.
We built UpsideHero to model the real numbers — actual debt service, actual expenses, actual stress tests. Try Phase 1 free and see what your deals really look like.
