AduCalcEstimate
00 // CALIFORNIA · 2026

Know what an ADU actually costs to build.

Engineered cost, rent, and payback estimates for California homeowners — calibrated from real 2024–2026 project data across 25 metros. No contractor spam. No single-number guesses.

Run my estimate →Feasibility quiz
Statewide build range
$175–$525/sqft
Avg monthly rent
$1,900–$3,800
Markets calibrated
25CA metros
01 // DATA PIPELINE
  • HCD.CA.GOV · 2025 handbook
  • RentCafe · metro rent index
  • Local MLS comps · 2024–2026
  • Contractor network · 40+ CA GCs
  • Zillow / Redfin lot data
02 // LIVE CA MARKETS
San Francisco$508/sqft●Oakland$449/sqft●Berkeley$467/sqft●San Jose$478/sqft●Fremont$463/sqft●Sacramento$368/sqft●Los Angeles$423/sqft●Santa Monica$478/sqft●Pasadena$441/sqft●Long Beach$412/sqft●Burbank$426/sqft●Glendale$430/sqft●Torrance$419/sqft●Anaheim$419/sqft●Irvine$459/sqft●Santa Ana$412/sqft●Huntington Beach$441/sqft●San Diego$397/sqft●Riverside$356/sqft●San Bernardino$349/sqft●Fresno$331/sqft●Stockton$338/sqft●Bakersfield$324/sqft●Santa Barbara$449/sqft●Ventura$412/sqft●
03 // PROCESS

Engineered for action —
not just information.

The same workflow a small GC uses to scope a bid, adapted for homeowners.

  1. 01STEP 01

    Answer 5 inputs

    Location, ADU type, size, finish tier, goal. Takes under two minutes.

    City/ZIP → Type → Size → Finish → Goal
  2. 02STEP 02

    Engineered estimate

    Live cost range, monthly rent, annual yield, and net payback calibrated to your city.

    Range · Rent · Payback · Yield
  3. 03STEP 03

    Ship or refine

    Download the spec sheet, take the feasibility quiz, or talk to a California ADU specialist.

    PDF · Quiz · Specialist
04 // ANATOMY

Every estimate is itemized —
not a round number.

Here's how a mid-finish 850 sq ft detached ADU in Sacramento breaks down. Every line is a bid-sheet category your GC will recognize.

Scope850 sqft · Detached · 1bd/1ba
MarketSacramento
FinishMid · builder +
Timeline10–14 months
EST · SACR-850-MIDv2026.04
Line itemLowHigh
Soft costs (design, permits, utility hookups)$28K$42K
Site prep & demo$12K$24K
Foundation & framing$48K$64K
MEP — electrical, plumbing, HVAC$32K$46K
Envelope — roof, windows, siding$38K$52K
Interior finishes, fixtures, appliances$52K$72K
GC overhead & profit (15–18%)$28K$44K
Engineered total$238K$344K
MID-PAGE CHECKPOINT

Get your own range before you compare bids.

Five inputs produce a source-backed cost, rent, and payback range. Your information is used to email your estimate — not to blast your project to contractors.

Run my estimate →
05 // COST DRIVERS

What actually moves the number.

Six variables explain ~80% of the spread between two otherwise identical ADU projects. We surface all of them in your estimate.

+15–28%

Bay Area labor premium

Skilled trades in SF, Oakland, San Jose, and Berkeley charge a measurable premium over Sacramento or the Inland Empire.

+$18–45K

Utility connections

Separate electrical service, sewer lateral, and water stub can add major cost if the existing house panel is full or the sewer is distant.

+$12–30K

Hillside or tight lot

Grading, retaining walls, crane access, or compact equipment all compound quickly on sloped or narrow-access sites.

–$60–120K

Garage conversion

Reusing an existing foundation and envelope drops per-sqft cost materially — but comes with its own ceiling-height and egress gotchas.

+$25–50K

High-end finish tier

Quartz, custom cabinetry, hardwood, upgraded windows, and mini-splits push an 850 sq ft unit into the $400K+ territory fast.

+$8–20K

Permit & impact fees

Capped by state law for ADUs under 750 sqft, but can still accumulate across plan-check, school-district, and utility-district fees.

06 // SERVICE AREAS

25 California markets, each tuned.

View all 25 markets →
SAN FRANCISCO
→
$370K–$493K
$/sqft$508
Rent/mo$3,475
OAKLAND
→
$327K–$436K
$/sqft$449
Rent/mo$2,800
BERKELEY
→
$340K–$454K
$/sqft$467
Rent/mo$2,975
SAN JOSE
→
$348K–$464K
$/sqft$478
Rent/mo$3,125
FREMONT
→
$337K–$450K
$/sqft$463
Rent/mo$2,900
SACRAMENTO
→
$268K–$357K
$/sqft$368
Rent/mo$1,925
LOS ANGELES
→
$308K–$411K
$/sqft$423
Rent/mo$2,650
SANTA MONICA
→
$348K–$464K
$/sqft$478
Rent/mo$3,225
PASADENA
→
$321K–$429K
$/sqft$441
Rent/mo$2,800
LONG BEACH
→
$300K–$400K
$/sqft$412
Rent/mo$2,575
BURBANK
→
$311K–$414K
$/sqft$426
Rent/mo$2,650
GLENDALE
→
$313K–$418K
$/sqft$430
Rent/mo$2,650
07 // REGULATORY

The 2026 California
ADU rulebook, decoded.

State law preempts most local restrictions. Here are the six provisions that shape what you can build.

Full laws guide →
  • SB 9 / SB 10CA

    By-right ADU approval

    Single-family lots in California can generally add one ADU and one JADU by right — no discretionary review.

  • AB 2221CA

    60-day approval clock

    Cities must approve or deny a complete ADU application within 60 days, or it's deemed approved.

  • AB 976CA

    Owner-occupancy banned

    Jurisdictions cannot require the owner to live on-site — ADUs can be pure rental investments.

  • AB 1033CA

    Condo-conversion option

    2024+: cities may allow ADUs to be sold separately from the primary home as a condo.

  • Gov. Code § 65852.2CA

    Impact-fee cap

    ADUs under 750 sq ft are exempt from impact fees; larger units pay fees scaled to size.

  • Title 24 · 2025CA

    Energy code

    New ADUs must meet 2025 Title 24 — typically heat pumps, EV-ready wiring, and high-performance envelope.

08 // METHODOLOGY

How we tune the numbers.

Every output on AduCalc is traceable to a documented engine. No hand-waving, no “average” California number.

Cost engine

$/sqft base curves tuned per ADU type (detached, attached, garage conversion, JADU), modulated by a city-level labor/overhead multiplier and a finish-tier factor.

Rent engine

Metro $/sqft rent baseline at a 600 sqft reference, adjusted by a size-elasticity curve and a finish premium. Vacancy default: 5%.

ROI engine

Gross yield = annual rent / build cost. Net payback applies a 20% default operating-expense load (taxes, insurance, mgmt, maintenance, reserves).

Feasibility

Five-question screen flags common blockers: condo ownership, steep slope, historic district, lot-coverage ceilings, setback conflicts.

10 // FAQ

Straight answers.

We strip the fluff. If it matters to your build, it's here.

Q.01How much does an ADU cost in California?
+
A typical detached ADU in California runs $275–$450 per sq ft before site-specific work, so an 800 sq ft unit usually lands between $220K and $360K. Garage conversions are cheaper ($175–$275/sq ft) and Bay Area markets are ~25% higher than Sacramento.
Q.02Are AduCalc estimates accurate?
+
We build directional ranges from 2024–2026 California ADU project data. Every estimate uses a range — not a single number — and shows you the multipliers behind it. Actual cost depends on site grading, utility connections, permits, and contractor bids.
Q.03Can I actually build an ADU on my property?
+
Most single-family properties in California can legally build an ADU thanks to state-level ministerial approval rules. Our 5-question feasibility quiz flags common blockers — tight lots, condos, hillside sites, historic districts.
Q.04Will you send my info to contractors?
+
No. When you unlock your full estimate, your info is used to email your results and — if you opt in — to connect you with a vetted California ADU specialist. We don't sell or syndicate leads.
Q.05Which California cities does AduCalc cover?
+
All of California, with sharper multipliers for 25 metros including Sacramento, Los Angeles, San Diego, San Jose, Oakland, San Francisco, Orange County, the Inland Empire, the Central Coast, and the Central Valley.
Q.06Is there a rental income calculator built in?
+
Yes — your ADU cost estimate already includes an estimated monthly rent, annual rent (post-vacancy), gross yield, and net payback after a default 20% expense load.
11 // NEXT STEP

Spec your ADU in
under two minutes.

Five inputs. A real engineered range. No contractor spam. Free while we're in California beta.

Run my estimate →Feasibility quizNO SIGN-UP REQUIRED · CA 2026
Run my ADU estimate →

No contractor spam · privacy-first