Duplex vs Triplex vs Fourplex: The Real Numbers for Investors

You're comparing duplex, triplex, and fourplex. Same asset class — 2–4 units — but the financing, vacancy math, and management load don't scale in a straight line. One empty unit in a duplex wipes out half your rent. In a fourplex, it's a quarter. That difference alone can change your whole strategy.

Here's what the numbers look like in real markets — Cleveland, Indianapolis, Kansas City — and what nobody tells you about crossing from two units to four.

Financing: FHA Up to Four, But the Rules Shift

All three qualify for an FHA loan at 3.5% down if you owner-occupy. Same entry point. Same 12-month residency requirement. Same MIP until you refi or hit 20% equity.

The wrinkle: triplexes and fourplexes must pass the self-sufficiency test. Gross rent × 75% has to cover full PITIA — principal, interest, taxes, insurance, MIP. Duplexes are exempt. No test. No math to run.

So a $420,000 fourplex with $4,200/month gross rent needs $3,150 to cover PITIA. If your PITI runs $3,400, it fails. Hard stop. You'd need conventional (15–25% down) or a different property. We've seen fourplexes in Cleveland and Indianapolis pass easily; softer rural markets can trip you up. Run the test before you fall in love with a listing.

Conventional treats 2–4 units as residential. Fannie/Freddie. 30-year fixed. 15% down for owner-occupied, 20–25% for investment. No self-sufficiency test. The financing gap between duplex and fourplex isn't the loan structure — it's the price. A fourplex costs more, so your down payment and PITI scale up. But you get four income streams instead of two.

Vacancy Impact: Where the Fourplex Wins

This is the silent differentiator. Lose one tenant in a duplex and you've lost 50% of your income. In a triplex, 33%. In a fourplex, 25%.

Run the numbers. Duplex at $2,800 gross rent, one unit vacant: $1,400. Your PITI doesn't care. You're covering the gap out of pocket. Fourplex at $4,200 gross, one unit vacant: $3,150. Still three units paying. The vacancy rate cushion matters — especially in markets where turnover runs 2–4 weeks between tenants. Budget 5–8% vacancy and the fourplex structure absorbs it better.

That's why many investors call the fourplex the sweet spot for cash flow and risk. You're not betting the whole property on two tenants. You've got diversification under one roof.

Price Per Unit: Economies of Scale

Duplexes run $150–200K per unit in Midwest markets. Fourplexes often $100–150K per unit. Same city, same neighborhood — you're paying less per door as you add units.

Cleveland: duplexes $280–380K ($140–190K/unit), fourplexes $380–520K ($95–130K/unit). Indianapolis: duplexes $220–320K ($110–160K/unit), fourplexes $340–480K ($85–120K/unit). Kansas City: duplexes $260–360K ($130–180K/unit), fourplexes $380–520K ($95–130K/unit).

The trade-off: higher total price. A $480,000 fourplex means $16,800 down with FHA (3.5%) or $96,000 with conventional (20%). You need more capital. But you're buying four doors for less per door than two. The 1% rule still applies — gross rent should be at least 1% of purchase price. A $480K fourplex needs $4,800/month. That's $1,200/unit. If your market supports $1,200 for a 2-bed in that neighborhood, the deal pencils. If not, walk.

Cash Flow Scaling: More Units, More Income, More Management

Here's where it gets interesting. A duplex in Kansas City: $320,000, $2,800 gross ($1,400/unit). PITI at 6.75%: $2,400. Minus 5% vacancy ($140), minus 10% maintenance ($280): $1,980 net. That's $580/month cash flow before reserves.

Same market, fourplex: $440,000, $4,400 gross ($1,100/unit). PITI: $3,300. Minus 5% vacancy ($220), minus 10% maintenance ($440): $3,440 net. $140/month cash flow. Lower per-unit rent, higher PITI. The fourplex might not cash flow as well on paper — but you've got four tenants. Lose one and you're still at 75% occupancy. The duplex loses one and you're at 50%. The 50% rule says operating expenses eat about half of gross. Run both through the 1% rule and the 50% rule. The fourplex often wins on risk-adjusted returns, not raw dollar flow.

Management Complexity: Two Tenants vs Four

A duplex means two leases. Two renewals. Two move-in/move-out cycles. One shared roof, one shared water heater, one insurance policy.

A fourplex means four. Four lease expirations that might land in the same quarter. Four tenants who might not like each other. More noise complaints. More parking disputes. More coordination when the shared HVAC goes out.

It's not twice the work — it's more like 1.5x for a triplex, 2x for a fourplex. But the emotional load is real. You're not just a landlord. You're a referee. And when one tenant plays music at 2 AM and another bangs on your door, you're the one they call.

The upside: you learn faster. Four tenant cycles in year one teach you screening, lease language, and turnover costs in a way two don't. By the time you scale to property #2, you've already handled the hardest parts of small multifamily. The house hacking path — live in one unit, rent the rest — works for all three. Duplex: one tenant. Triplex: two. Fourplex: three. Your housing cost drops as you add units. The trade-off is more neighbors. More relationships. More things that can go wrong.

Who Should Choose Which

Pick the duplex if: You want the simplest possible house hack or first rental. One tenant, one lease, one relationship. You're okay with 50% vacancy risk because the learning curve matters more than the extra margin. You'd rather have lower PITI and sleep well than squeeze another $200 in rent from a third unit. Duplexes also tend to resell faster — the buyer pool for 2-unit is larger than for 4-unit.

Pick the triplex if: You want the middle ground. Three income streams, 33% vacancy impact, still manageable. Many investors call triplex the sweet spot. FHA self-sufficiency applies — run the test. Triplexes are rarer than duplexes in most markets, which can mean less competition when buying and more scarcity when selling.

Pick the fourplex if: You want maximum vacancy diversification and you're willing to manage four tenants. You've got the capital for the higher down payment. You're comfortable with the self-sufficiency test. Fourplexes often pencil at lower price-per-unit — you're buying efficiency. But plan to hold longer. The pool of buyers who want four units is smaller.

The Break-Even Check

Before you offer on any of them, run break-even occupancy. PITI divided by gross potential rent. That tells you what occupancy level you need just to cover costs.

Duplex at $2,400 PITI and $2,800 gross: 85.7%. You need 86% occupancy to break even. One unit vacant for a month and you're covering the gap.

Fourplex at $3,300 PITI and $4,400 gross: 75%. You could lose 25% of income and still cover the mortgage. That's the fourplex advantage — the structure absorbs vacancy better.

Both work. The Small Multifamily Investing guide walks through financing, deal analysis, and the full 2–4 unit playbook. The difference is fit. Duplex: simpler. Fourplex: more income, more moving parts, better vacancy cushion.

One more wrinkle: house hacking changes the math. Live in one unit, rent the rest. Duplex: one tenant. Triplex: two. Fourplex: three. Your housing cost drops as you add units — but so does your privacy. Fourplex means three sets of neighbors under the same roof. Some investors love the income. Others can't wait to move out. Know which you are before you buy.

Run your own numbers. Then pick the one that matches your tolerance for tenant management and your target cash flow. There's no wrong answer — only the right fit for your situation.