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ADU Cost Calculator

Our interactive calculator is being built with real contractor data. In the meantime, use our detailed cost guides below — they cover common ADU types with dated estimates and scope notes.

Detailed Cost Guides

Published estimates and examples from contractor, permit, and vendor sources. Check each guide for its date, geography, and included scope.

How Much Does an ADU Cost?Complete 2026 pricing by type, size, and region
ADU Cost Per Square FootWhy per-sq-ft costs vary and what drives them
Prefab ADU CostFactory-built pricing, delivery, and install
400 Sq Ft ADU CostBudget breakdown for one-bedroom units
Garage Conversion ADU CostConverting existing space for less

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Be the first to use our interactive ADU cost estimator with region-specific data after the underlying sources have been reviewed.

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Need a Quick Estimate Now?

Use our ADU Feasibility Engine to get an initial planning estimate based on the information you provide. It does not verify parcel boundaries, easements, utility capacity, or permit approval.