The Basic Math
Real estate investing comes down to three numbers: what you pay, what it earns, and what it costs to own. Everything else is marketing.
Cap Rate
Net Operating Income (NOI) divided by purchase price. A $200,000 property generating $14,000/year NOI (after expenses, before mortgage) has a 7% cap rate. Cap rates of 5-8% are typical for residential rentals. Under 5% is expensive; over 8% signals higher risk.
Cash-on-Cash Return
Annual cash flow divided by your total cash invested. If you put $50,000 down and net $4,000/year after all expenses and mortgage, your cash-on-cash return is 8%. This is the number that matters for your personal wealth building.
The 1% Rule
Monthly rent should be at least 1% of purchase price. A $200,000 property should rent for $2,000/month. This is a screening tool, not a guarantee of profitability. Properties that pass the 1% rule in 2026 are increasingly rare in hot markets.
Real Numbers: A Typical Rental
Purchase price: $200,000 (25% down = $50,000 invested) Mortgage: $150,000 at 7% = $998/month Monthly rent: $1,600
| Line Item | Monthly | Annual |
|---|---|---|
| Rent collected | $1,600 | $19,200 |
| Mortgage P&I | -$998 | -$11,976 |
| Property tax (1.1%) | -$183 | -$2,200 |
| Insurance | -$125 | -$1,500 |
| Maintenance (10% of rent) | -$160 | -$1,920 |
| Vacancy (8% of rent) | -$128 | -$1,536 |
| Property management (8%) | -$128 | -$1,536 |
| Net cash flow | -$122 | -$1,468 |
This property is cash-flow negative. That’s the reality for many rentals purchased at current prices and rates. The investor is paying $122/month for the privilege of owning — betting on appreciation and mortgage paydown to create long-term wealth.
Where the Real Returns Come From
1. Principal Paydown
Your tenant’s rent pays down your mortgage. In year one, roughly $2,400 of a $12,000 mortgage goes to principal. By year 10, it’s $4,200/year. This is forced equity building even on a cash-flow-negative property.
2. Appreciation
Historical average: 3-4% annually. On a $200,000 property with 75% leverage, 3% appreciation = $6,000 value gain on $50,000 invested = 12% return on equity from appreciation alone.
3. Tax Benefits
Depreciation ($200,000 building / 27.5 years = $7,273/year) creates a paper loss that offsets rental income. If your rental shows a $1,468 cash loss and $7,273 depreciation, you have a $8,741 paper loss against your other income (subject to passive activity rules and income limits).
4. Rent Growth
Rents historically increase 3-5% annually. The same property renting at $1,600 today may rent for $2,100 in 5 years while the mortgage stays at $998. Cash flow turns positive without any action on your part.
The Risks Nobody Mentions
- Vacancy: Even one month vacant costs $1,600 and wipes out months of cash flow
- Major repairs: A $5,000 plumbing repair represents more than 3 years of thin cash flow
- Problem tenants: Eviction costs $3,000-$8,000 and takes 2-6 months in tenant-friendly states
- Concentration risk: A single property in a single market with a single tenant
- Illiquidity: Selling takes 60-120 days and costs 8-10% in transaction fees
- Interest rate risk: If you need to refinance, rates may be higher
REITs vs. Direct Ownership
Publicly traded REITs offer real estate exposure without the management headache:
- Liquidity: Buy and sell instantly
- Diversification: Hundreds of properties across geographies
- Professional management: No midnight maintenance calls
- Returns: REIT index funds have returned 8-11% annually long-term
The trade-off: no leverage benefit, no depreciation (for individuals), no control, and correlation with stock market during downturns.
Getting Started
If you’re serious about rental investing:
- Build a $20,000+ emergency fund separate from your investment capital
- Get pre-qualified for investment property financing (25% down minimum, rates ~0.5-0.75% above primary residence)
- Learn your target market’s rent-to-price ratios using HomeStats state data
- Run the numbers on 20 properties before making an offer on one
- Get a property inspection by an investor-experienced inspector, not just a buyer’s inspector
The W-2 Trap covers the complete investment framework for building wealth on employment income, including when real estate investing makes sense versus other asset classes.