Fourplex & Multifamily Development Plans (with Cost Estimate)

Whether you are house-hacking a duplex or developing a fourplex or small apartment building, the numbers have to work before you build. We draw the plans and hand you an RSMeans-based cost estimate so you can budget, finance and pitch lenders with confidence.

In 2026, a fourplex typically costs $300,000–$1.3M to build (about $750,000 average, or $120–$300 per square foot) — roughly $75,000–$325,000 per unit depending on size, finish and location.

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Fourplex: $300k–$1.3MCost estimate includedFinancing-ready plans

Fourplex & Multifamily Development Plans (with Cost Estimate)

Duplex → multifamilyPlans + RSMeans cost estimate

What's included

Site plan with efficient unit stacking and parking ratios
Floor plans for each unit type — fully dimensioned
Exterior & interior elevations
MEP layouts (mechanical, electrical, plumbing)
Editable CAD/DWG files
RSMeans-based construction cost estimate
Permit planning documentation

Drawn for income and financing

Multifamily is an investment first. We plan for rentable square footage, efficient cores, code-driven layouts and parking ratios — and give you a cost estimate you can take straight to a construction lender.

Fourplex build cost (2026)

Build level	Total cost	Per unit / sq ft
Basic / shell	$300k	~$75k per unit · $120/sq ft
Standard turnkey	~$750k	~$187k per unit · $200/sq ft
Custom / premium	$1.3M+	~$325k per unit · $300/sq ft

Excludes land. Duplex and triplex projects scale down from these figures. Get your exact number below.

Get an exact number for your project

A designer prepares your full package with an RSMeans-based cost estimate — start the short brief.

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Frequently asked questions

Do you plan duplexes and triplexes too?+

Yes — from a 2-unit duplex through triplex, fourplex and larger multifamily. Choose your unit count when you start the brief.

Is the cost estimate really included?+

Yes. Every development package includes an RSMeans-based construction cost estimate for your unit mix and location — most firms charge extra for this.

Can I use the plans for a construction loan?+

Yes. The plans plus the cost estimate are exactly what lenders ask for; the package is drawn permit-minded with permit planning documentation.

How fast will I hear back?+

A designer reviews your brief and contacts you within 1 business day.

Run the numbers on your multifamily project

Tell us your unit count and location — a designer prepares your plans and an RSMeans-based cost estimate, and contacts you within 1 business day.