ADU Cost Estimator

Thinking of building a guest house? Estimate your construction budget based on size, site complexity, and quality of finishes.

ADU Type

Square Footage (sq ft)

Finish Quality

Difficult Site Prep (Slope/Rock)

Estimated Total Cost

$150,000

Range: $135k – $165k

Is an ADU worth the investment?

I genuinely believe that an ADU is one of the few home improvements that actually pays for itself. In high-demand markets like California or Florida, a $150k ADU can add $250k to your property value and generate $2,000/month in rent. That’s math that makes sense.

Soft Costs vs Hard Costs: This calculator estimates the "hard costs" (lumber, labor, plumbing). Don't forget that you'll spend another $15,000–$25,000 on "soft costs" like architectural plans, permits, and utility hookup fees. Check your local zoning laws before you buy a single board!

Cost Breakdown:

Foundation & Framing: Usually 30-40% of the budget.
Plumbing & Electrical: More expensive than you think for small units.
Permits: Can vary wildly from $2k to $15k depending on your city.