Homeowner Tools
Free ADU return calculator

Will your ADU pay for itself, and how fast?

Rent, running costs, the property tax an ADU adds, and the payback period, on real California numbers. Built from the same cost model as our budget calculator.

Your ADU and your market

Directional planning only, not an appraisal, a tax opinion or investment advice. Nothing is stored until you choose to unlock your results.

The unit
SF
New-construction ADUs go up to 1,200 SF.
Rents and build costs both move with the region.
I set this from the size. Change it if your plan is different.
Cost and rent (prefilled from our numbers, overwrite with yours)
$
Typical expected cost for this unit: construction with finishes, plus city fees. Have a real bid? Add the fees and anything it leaves out.
$
Typical for this size in your area.
How you pay for it
Running it
$
Zero if the unit has its own meters and the tenant pays.
$
A rented ADU usually needs its own landlord cover. Ask your agent.
🔒 One step to your full read
Your ADU return
$0,000 / mo · 0.0 yrs

Where should I send it?

Enter your email to unlock your monthly cash flow, return on cash, payback period, the property tax the ADU adds, what it may do to your home's value, and the rental rules that apply to your unit.

I never sell your information, and I never hand it to a contractor unless you ask me to match you with one. You will get your results, my free homeowner checklist, and occasional pre-construction tips for California homeowners. Unsubscribe any time, one click, no hard feelings. Privacy policy.

$0 / mo
Return on cash
0%
Payback
0 yrs
What it may do to your home's value

The return is decided before the first footing.

Size, type and the bid you sign set every number above. Get a straight read on your lot and your plan before you commit.

Book a 30-min advisory call Get the ADU guide

Build Advisor CA provides independent, pre-construction advisory and educational guidance. We are not licensed contractors, appraisers, real estate brokers, attorneys, tax advisors, or financial advisors, and nothing here is an appraisal, a rent survey, tax advice, or investment advice. Costs, rents, taxes, and values are directional illustrations only and depend on your property, city, market, and terms. Rent figures start from HUD FY2027 Small Area Fair Market Rents by ZIP code, adjusted against 2026 asking rents (regional averages where HUD does not cover a ZIP). They assume a long-term, unfurnished rental to an unrelated tenant, and are not ADU-specific surveys. Confirm every number with the appropriate licensed professional before you build or borrow.