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Free preliminary planning tool

Preliminary ADU Cost Calculator

Carry your model forward and build a transparent preliminary cost and financing scenario in 9 simple steps.

Preliminary estimate

Project setup

Your selections are saved automatically.

Step 1 of 9 · Property

Progress saved

Step 1 of 9

Property

Confirm the project location and optional property dimensions.

Select a suggestion to auto-fill the city and ZIP code.

Parcel and existing home size auto-fill when you start from a property check. Both are optional and only refine your estimate.

Local cost context

Need San Jose ADU cost and permit context?

Compare the calculator with San Jose-specific size rules, permit steps, utilities, preapproved-plan eligibility, and 2026 local guidance.

San Jose ADU cost guide

Let’s build your ADU

Your property.
Your next chapter.

Explore the possibilities for your California property.

Check my property
Architectural concept of a modern California ADU in a landscaped garden, shown in natural daylight
Design concept

Let’s talk about your project.

(650) 400-7606sales@adu.zone

San Jose office

84 West Santa Clara Street Suite 700
San Jose, CA 95113
(650) 400-7606Get directions

Walnut Creek office

1990 N California Blvd, 8th Floor
Walnut Creek, CA 94596
(925) 744-5040Get directions
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