Cost of an ADU in Florida (2026)
- Studio (200–400 sq ft): $90,000–$150,000
- 1-Bedroom (400–700 sq ft): $140,000–$220,000
- 2-Bedroom (700–1,000 sq ft): $200,000–$320,000+
- Basic conversion (insulation, drywall, electrical, plumbing): $60,000–$110,000
- Full conversion with kitchen and bathroom: $80,000–$140,000
- Studio–1BR attached suite: $110,000–$180,000
- 2BR attached addition: $160,000–$250,000
- Prefab unit + installation: $80,000–$160,000 (excluding land)
ADU costs in Florida vary significantly depending on ADU type, size, location, site conditions, and current construction market pricing. This guide gives realistic ranges based on 2026 South Florida market conditions.
Cost by ADU Type
Detached Backyard ADU
The most popular and most expensive ADU type. Requires its own foundation, framing, roof, and utility connections.
Garage Conversion
Often the most cost-effective ADU type since the structure already exists. Cost depends heavily on the condition of the existing garage and required upgrades.
Attached ADU (Addition)
Built as an addition to the existing home. Costs depend on connection complexity.
Guest House / In-Law Suite (Prefab)
Prefabricated ADU structures have become more popular in Florida. Cost-effective but require site prep and utility connections.
Key Cost Drivers
1. Site conditions — Sloped lots, poor soil, or limited access increase costs
2. Utility connections — Running new water/sewer lines can add $15,000–$40,000
3. Permitting fees — Range from $3,000–$10,000 in South Florida
4. Finishes and appliances — Budget vs. premium can swing $20,000–$50,000
5. Construction market — Labor costs in Miami-Dade are 15–20% higher than statewide average
Does an ADU Make Financial Sense?
At current Miami market rents ($1,800–$3,200/month for 1BR), a $180,000 ADU can achieve a 12–18 year payback period — and adds long-term property value. Broward and Palm Beach rates are similar.
Request a property review from ADU4Florida to get a realistic cost direction for your specific property.