The 1% Rule Is Dead — Here's What Actually Evaluates a Deal
The old "1% rule" (monthly rent should be 1% of purchase price) made sense when interest rates were 4% and most markets were cheap. Today, in most U.S. cities, 1% properties don't exist — and in the ones that do, expenses and financing costs often make them cash-flow negative anyway. Sophisticated investors use four metrics to evaluate deals: cap rate, cash-on-cash return, gross rent multiplier, and IRR.
Net Operating Income: The Foundation
Every rental property metric starts with NOI (Net Operating Income):
NOI = Gross Rental Income − Vacancy − Operating Expenses
Operating expenses include: property taxes, insurance, property management (typically 8–10% of rent), maintenance and repairs (budget 1% of property value/year), utilities paid by owner, and capital expenditure reserves (roof, HVAC, appliances — budget 5–10% of rent).
NOI does not include mortgage payments — those are financing costs, not operating costs.
Example Property Analysis
Property: $380,000 purchase price, 25% down ($95,000), $285,000 mortgage at 7% for 30 years.
Rental income: $2,400/month = $28,800/year
| Income/Expense | Annual Amount |
|---|---|
| Gross rental income | $28,800 |
| Vacancy (7%) | −$2,016 |
| Effective gross income | $26,784 |
| Property taxes | −$4,200 |
| Insurance | −$1,800 |
| Property management (9%) | −$2,592 |
| Maintenance (1% of value) | −$3,800 |
| CapEx reserve (8% of rent) | −$2,304 |
| NOI | $12,088 |
Metric 1: Cap Rate
Cap Rate = NOI ÷ Property Value × 100
$12,088 ÷ $380,000 = 3.18%
Cap rate represents the return if you bought the property all-cash. Typical benchmarks:
- Urban Class A markets: 3–5%
- Suburban residential: 5–7%
- Value-add or rural: 7–10%+
At 3.18%, this property has a thin cap rate — typical for a competitive metro area. Cap rate alone doesn't tell you if it's a good investment; you also need to analyze leverage.
Metric 2: Cash-on-Cash Return
Cash-on-Cash = Annual Pre-Tax Cash Flow ÷ Total Cash Invested × 100
Annual mortgage payment: $285,000 at 7% for 30 years = $1,897/month = $22,764/year
Annual cash flow = NOI − Mortgage = $12,088 − $22,764 = −$10,676/year
This property is cash-flow negative by $889/month. Cash-on-cash: −$10,676 ÷ $95,000 = −11.2%
This deal only works if appreciation is significant. At 4% annual appreciation, the $380,000 property gains $15,200/year in value — more than offsetting the cash flow deficit. This is speculative; cash-flow-positive properties are lower risk.
Metric 3: Gross Rent Multiplier (GRM)
GRM = Purchase Price ÷ Annual Gross Rent
$380,000 ÷ $28,800 = 13.2
Lower GRM = better value. Rules of thumb:
- GRM under 8: potentially strong cash flow deal
- GRM 8–12: reasonable in most markets
- GRM above 14: appreciation play, not cash flow
GRM is a quick screening tool — use it to filter properties before doing full analysis.
Metric 4: Total Return (Appreciation + Cash Flow + Equity)
True ROI on a rental includes three sources of return over the holding period:
- Cash flow: Cumulative annual cash flows (positive or negative)
- Appreciation: Property value increase at sale
- Equity paydown: Principal paid down through mortgage payments (this is forced savings)
Year 5 analysis on our example (4% annual appreciation):
- Cumulative cash flow: −$10,676 × 5 = −$53,380
- Appreciation gain: $380,000 × (1.04^5 − 1) = $82,599
- Equity paydown: ~$18,000 in principal paid over 5 years
- Net 5-year gain: −$53,380 + $82,599 + $18,000 = $47,219
- Cash invested: $95,000 + closing costs ~$8,000 = $103,000
- 5-year total return: $47,219 ÷ $103,000 = 45.8% total, or ~7.8% annualized
The 50% Rule for Quick Screening
Experienced investors use the 50% rule: assume operating expenses (excluding mortgage) will equal 50% of gross rent. On $2,400/month rent: $1,200 goes to expenses, $1,200 is NOI. Compare this to your mortgage payment to quickly estimate cash flow. This is a rough heuristic, not a substitute for full analysis.
Bottom Line
Evaluate rental properties using all four metrics together. Cap rate for market comparison, cash-on-cash for leverage analysis, GRM for quick screening, and total return IRR for long-term investment decisions. Never buy solely based on appreciation expectations — model the property assuming zero appreciation and ensure you're comfortable with that outcome. Use the CalcPeek investment calculator to model investment returns and compound growth scenarios for any asset class.