Why It Matters
If you want $10,000/month in net rental income and your average property nets $300/door after all expenses, you need 34 doors. That's your door count goal. It's the simplest equation in real estate: Target Income ÷ Cash Flow Per Door = Doors Needed.
But the number isn't as simple as the formula. A 34-door portfolio of $150,000 SFRs requires $5.1 million in real estate. At 75% LTV, that's $1.275 million in equity. Building that takes years of strategic acquisitions, refinances, and reinvestment. The door count goal becomes the anchor for your ten-year plan—every acquisition decision either moves you closer or further from that number.
Smart investors set two numbers: a cash flow door count (how many doors for your income target) and a net worth door count (how many doors for your equity target). They're not always the same. A free-and-clear property generates more cash flow per door but fewer total doors for the same capital. A leveraged portfolio creates more doors but less cash flow per door. Your strategy depends on which goal takes priority.
At a Glance
- Formula: Target Monthly Income ÷ Net Cash Flow Per Door = Door Count Goal
- Typical targets: 10–15 doors (part-time income), 25–40 doors (full-time replacement), 50+ doors (wealth building)
- Average net per door: $200–$400/month for SFRs, $150–$300 for multifamily units
- Key variable: Cash flow per door varies dramatically by market and property type
- Review: Recalculate annually as cash flow per door changes
How It Works
Backward calculation
Start with your target monthly income. Let's say $8,000/month. Research average net cash flow per door in your target market. In a Midwest market: $250–$350/door. At $300/door: $8,000 ÷ $300 = 27 doors. At $250/door: 32 doors. At $350/door: 23 doors. Your range is 23–32 doors. Plan for the conservative estimate.
Phased acquisition
27 doors in 10 years means roughly 3 doors per year. Years 1–3: 2 doors/year (learning phase). Years 4–7: 3–4 doors/year (scaling phase). Years 8–10: 1–2 doors/year (optimization phase). The pace isn't linear because capital availability and experience grow over time.
Cash flow per door assumptions
The $300/door assumption must be validated against actual portfolio performance. Track trailing 12-month net income per door including vacancy, maintenance, CapEx reserves, management fees, and mortgage payments. If actual performance is $220/door, your door count goal increases to 37. If it's $380/door, you only need 22.
Adjusting for appreciation and paydown
As mortgages amortize and properties appreciate, your equity per door grows. After 10 years, a $150,000 property might be worth $200,000 with $80,000 in equity. Your 27-door portfolio could represent $2.16 million in equity. Some investors prioritize this net worth goal over cash flow and plan to eventually pay off mortgages for maximum per-door income.
Real-World Example
Lisa in Birmingham, Alabama wants to replace her $7,500/month salary. Her first 4 rentals net an average of $285/door after all expenses. Door count goal: $7,500 ÷ $285 = 27 doors (rounded up). She maps out a 9-year plan: years 1–3 she already has 4 doors. Years 4–6: add 3/year (13 total). Years 7–9: add 4–5/year (27 total). Capital requirement: roughly $35,000 per door in down payment and rehab. Total capital needed: 23 more doors × $35,000 = $805,000. Funded by: savings ($25,000/year × 9 = $225,000), cash flow reinvestment ($285 × growing door count), and 3 cash-out refinances ($150,000 total). Lisa hits 24 doors by year 8 and revises her goal to 30 doors after rents increase.
Pros & Cons
- Creates a clear, measurable portfolio target
- Drives backward planning for capital and acquisition pace
- Prevents aimless, unfocused investing
- Easy to communicate to partners, lenders, and mentors
- Scales naturally with income growth or lifestyle changes
- Oversimplifies by treating all doors as equal
- Cash flow per door varies significantly by market and property age
- Doesn't account for appreciation, tax benefits, or equity growth
- Can encourage chasing door count over deal quality
- Market conditions may make the target unrealistic in a given timeframe
Watch Out
- Door count vanity: Owning 30 doors that each net $100/month isn't better than owning 15 doors that each net $300/month. Quality per door matters more than raw count. Don't buy marginal deals just to hit a number.
- Ignoring total return: Cash flow per door is only one component of return. Appreciation, principal paydown, and tax benefits add $150–$300/month in total return that door count goals often ignore. Factor in total return when setting targets.
- Static assumptions: Your $300/door assumption will change. Taxes increase, insurance premiums rise, maintenance costs grow with property age. Recalculate annually with actual numbers, not the projections from year 1.
- Comparison trap: Another investor's 50-door portfolio in a low-cost market may produce less income than your 20-door portfolio in a stronger market. Door count is personal to your market and strategy.
Ask an Investor
The Takeaway
A door count goal gives your portfolio a destination. Calculate it from your income target and per-door cash flow, then build a phased acquisition plan to get there. But treat the number as a guide, not a mandate—buying 27 good properties matters infinitely more than rushing to hit 27 of any quality.