Why It Matters
You can't compare a 12-unit at $847,000 to an 8-unit at $720,000 by sticker price — different unit counts make the raw number meaningless. Cost per unit solves that: divide total acquisition cost (purchase price + closing costs + immediate rehab) by unit count and you're comparing apples to apples. In Class B secondary markets, $70K–$120K/unit is the 2025 range. Below $90K/unit, you're in value-add territory — below-market rents, deferred maintenance, or both. New construction runs $200K–$350K/unit. Cost per unit is the first number that tells you whether a deal deserves a full underwrite.
At a Glance
- What it is: Total acquisition cost divided by number of units — normalizes deal size for apples-to-apples comparison
- Formula: Cost Per Unit = (Purchase Price + Closing Costs + Immediate Rehab) / Number of Units
- Class B secondary markets (2025): $70K–$120K/unit typical range
- Value-add signal: Below $90K/unit — check for below-market rents or deferred maintenance
- New construction: $200K–$350K/unit depending on market and submarket
- Common mistake: Using only purchase price — always include closing costs and immediate rehab in the numerator
Cost Per Unit = Total Acquisition Cost / Number of Units
How It Works
Total acquisition cost, not just purchase price. The formula requires three components: purchase price, closing costs, and immediate rehab. Skip closing costs and you're understating your basis by 2–3%. Skip rehab and you're comparing a renovated deal against one needing $4,000/unit in work — a comparison that means nothing.
The normalization mechanic. A 12-unit at $916,175 total cost gives you $76,348/unit. An 8-unit at $720,000 gives you $90,000/unit. Without cost per unit, you'd look at the 8-unit's lower sticker price and assume it's cheaper. It isn't. The 12-unit costs $13,652 less per door even after accounting for $48,000 in immediate rehab. That differential compounds across every metric — your cap rate, your cash-on-cash return, your return on equity — because the denominator of every return calculation gets smaller.
Benchmarks anchor your underwriting. Class B secondary markets: $70K–$120K/unit. Class A urban core: $150K–$250K/unit. Below $90K/unit typically flags below-market rents or deferred maintenance — the entry point for a value-add plan. At $95K/unit for a turnkey Class B, you're buying at market and your ROI will price accordingly.
What cost per unit doesn't tell you. It doesn't account for rent levels. A deal at $70K/unit in a strong rent market is different from $70K/unit in a declining submarket. Always pair cost per unit with total return analysis and cap rate. Cost per unit gets you to the next conversation — it doesn't close it.
Real-World Example
Marcus is underwriting two multifamily listings in the same secondary market. The first is a 12-unit apartment at $847,000 asking price. His inspector flags $48,000 in immediate rehab — aging electrical panels, two units needing new flooring, one bathroom gut. His lender quotes 2.5% in closing costs: $21,175. Total acquisition cost: $916,175. Divided by 12 units: $76,348 per door.
The second listing is an 8-unit at $720,000, recently renovated, no immediate rehab. Closing costs: $18,000. Total: $738,000. Divided by 8 units: $92,250 per door.
The 8-unit is $127,000 cheaper by sticker price. But Marcus is paying $15,902 more per door — extra basis with no income advantage, since both buildings carry comparable market rents.
He runs the 12-unit's full underwriting. NOI: $87,600 annually. Cap rate: $87,600 / $916,175 = 9.56%. With 20% down ($183,235), first-year cash flow comes in at $24,600. Cash-on-cash return: $24,600 / $183,235 = 13.4%.
Marcus takes the 12-unit. Cost per unit told him in 60 seconds what raw price never could: he was buying $13,652/unit cheaper by accepting a known, scoped rehab.
Pros & Cons
- Normalizes deal size instantly — compare a 6-unit to a 24-unit in one calculation
- Works at the pre-LOI stage — fast filter before full underwriting
- Flags value-add opportunities when cost per unit falls below market benchmarks
- Forces correct basis math by including closing costs and rehab in the numerator
- Ignores rent levels — a low cost per unit in a weak rent market can still be a bad deal
- Doesn't capture unit mix — a 12-unit of studios costs less per door to operate than 12 two-bedrooms; cost per unit treats them identically
- Benchmarks shift by geography; national averages mislead in high-cost coastal markets or deep Midwest secondaries
- Rehab estimates at the underwriting stage are guesses — cost per unit is only as accurate as your rehab scope
Watch Out
Sellers routinely exclude rehab from their own cost-per-unit presentations. A broker marketing a deal at "$68,000/door" may be dividing the list price alone by unit count. When you add your inspector's $4,500/unit rehab estimate and 2.5% closing costs, the real number could be $78,000/door — still good, but not what was advertised. Always build the number yourself from all three components.
Don't cross-compare markets without adjusting benchmarks. A $95,000/unit deal in Indianapolis is expensive. A $95,000/unit deal in Denver is a find. Benchmarks are market-specific — using national averages to evaluate a local deal will send you in the wrong direction. Build a comp set of recently closed multifamily deals in your target submarket before applying any rule of thumb.
Ask an Investor
The Takeaway
Cost per unit normalizes multifamily acquisition cost regardless of deal size. Divide total acquisition cost — purchase price plus closing costs plus immediate rehab — by unit count and you can compare any two deals head to head. In Class B secondary markets, $70K–$120K/unit is the 2025 benchmark; below $90K signals a value-add opportunity. Pair it with cap rate and cash-on-cash return to complete the picture.