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ADU ROI & rental yield calculator

Will your ADU pay for itself? This estimates monthly cash flow (rent minus mortgage minus operating costs), years to breakeven, and cash-on-cash return — all using 2026 California construction-cost ranges and regional rent benchmarks.

Net monthly cash flow
+$0/mo
After mortgage + operating costs
Total project cost$225,000
Down payment$45,000
Loan amount$180,000
Monthly mortgage (P&I)$1,259
Operating costs (~$280/mo)$280
Years to break even on down— yr
10-year cash-on-cash ROI— %
What this includes
  • Mortgage P&I on the financed portion
  • Operating costs: property tax delta (~$200/mo on $250k ADU build), maintenance reserve (~$50/mo), small vacancy buffer (~$30/mo)
  • Linear cash-on-cash return — does NOT include appreciation or tax benefits
What this excludes (your upside)
  • Appreciation (CA real estate has averaged 4-6% annually long-term — adds substantial 10-year value)
  • Mortgage principal paydown (your equity grows even if cash flow is flat)
  • Depreciation tax benefit (consult a CPA — potentially $5-9k/year)
  • Adjusting rent over time (CA rents typically rise 3-5%/year)

Reality check: the ranges below are illustrative. Actual rents depend on neighbourhood, ADU type, and timing. Get a real rent comp from a local property manager before committing.

Find your city's rent benchmarks →

Typical California ADU rents (2026)

Use these as a sanity check on the rent input above. Real data from Zillow Rent Index + RentCafe averages, April 2026.

RegionStudio1BR2BR
Bay Area (SF / Oakland / SJ)$2,400$3,200$4,200
Los Angeles + OC$1,900$2,600$3,400
San Diego$2,000$2,700$3,500
Central Coast (SB / SLO)$1,800$2,400$3,000
Sacramento$1,400$1,900$2,500
Inland Empire$1,500$2,000$2,600
Central Valley$1,100$1,500$2,000

ROI calculation uses standard mortgage amortisation. Operating costs estimate assumes property-tax reassessment of the new structure (~1% of build cost per Prop 13 + local assessments) plus modest maintenance reserve. Cash-on-cash return = (annual cash flow / down payment). Real returns vary; this tool is illustrative, not advice.