LotFoundry: ADU Calculator

Could an ADU fit in your backyard? LotFoundry helps homeowners explore an accessory dwelling unit with a 3D lot model and estimates for build cost, rental income and payback. Start with a demo property, or look up your own address. Compare a backyard home for family, rental income or future plans before committing to design work. EXPLORE YOUR LOT Review available parcel information, estimated setbacks and building placement. Property data and coverage vary by location. The model is a starting point for planning, not a boundary survey. COMPARE YOUR OPTIONS Adjust your ADU concept and compare estimated construction costs, monthly rent and payback. Use the numbers to prepare questions for local professionals, rather than treating them as quotes or guaranteed returns. SEE A CONCEPT IN 3D Explore size, roof and finish options on a lot model. Check placement warnings as you compare possibilities for a small backyard home, granny flat or accessory dwelling unit. KEEP YOUR PLANNING TOGETHER Save scenarios to your account. An optional in-app purchase unlocks a Certificate of Feasibility, an early planning report you can review and share. Basic exploration does not require a certificate purchase. The purchase price is shown in the app before checkout. LotFoundry is an estimation and early planning tool. It does not issue permit approvals, appraisals, construction documents or investment guarantees. Confirm local rules, site conditions, costs and rents with qualified professionals before making a building decision.