The ADU Types People Ask For Most
ADUs come in a handful of forms, and the right one depends on your lot, budget and goal — these are the configurations we design most.
A standalone one- or two-bedroom home in the rear yard with its own entry — the most flexible and highest-value ADU when the lot has room.
Turning an existing garage into a living unit — the cheapest path to an ADU because the shell and slab already exist, if the structure allows it.
A new garage with a full apartment over it — parking below, rental or guest suite above, ideal for tighter lots.
A unit added to the main house with a separate entrance — lower site-work cost, good for aging parents or a home office with independence.
A compact unit carved from within the existing home, often under 500 sq ft — the lowest-cost, fastest-permitting option in many jurisdictions.
A small, efficient studio or one-bed tuned for maximum rent per square foot, with a durable, low-maintenance finish set.
Interactive estimate
What will a custom ADU cost to build?
Drag to your target size for a live 2026 build-cost range. Then get an exact, state-adjusted number — or start a custom plan drawn around it.
Typical a custom ADU range: $200–$400/sq ft (materials + labor, 2026)
Estimated build cost
$150,000 – $300,000
Midpoint ≈ $225,000
Estimate only. Site, finishes and region shift the total — a full report or custom plan pins it down.
Custom ADU Plans from $499
An ADU only pencils out if the plan fits your lot and local rules
Tell us your lot, goal and city — a designer prepares an ADU plan built to your setbacks, height limit and utilities.
What to Know Before You Design an ADU
These are the decisions that determine whether your ADU gets permitted, pencils out financially and actually feels like a home.
Most jurisdictions cap ADU square footage and height, and many set a maximum as a share of your lot or main house. The plan has to be drawn to your specific limits, which vary widely city to city.
Rear and side-yard setbacks decide where the ADU can sit and how big it can be. State ADU laws often reduce these, but the exact numbers shape the footprint from the first line.
Whether the ADU taps the main house’s water, sewer and power or gets its own service is a major cost and design decision — one that should be planned, not discovered at inspection.
Some cities still require an off-street space for the ADU; many have waived it near transit. This can change your whole site layout, so it belongs in the plan early.
The best ADU return comes from an efficient layout that maximizes rentable space per dollar built. An oversized ADU costs more and rarely rents for proportionally more.
Rules on renting, owner-occupancy and short-term use vary by state and city. Designing to your jurisdiction’s program keeps the project permittable and legal to rent.
Why ADU Plans Should Be Custom (or Heavily Modified)
A downloaded ADU plan assumes a generic lot, generic setbacks and a size limit that may not match your city at all. Because ADU rules are intensely local, a stock plan almost always needs re-fitting to your setbacks, height cap and utilities before a building department will accept it — modification fees plus delays usually cost more than starting from your lot.
Tell us your lot, goal and jurisdiction and our design team delivers a complete print-ready ADU plan set drawn to your local rules — typically in 5–7 business days with a free revision round included.
From $499 — designed for your lot
A fully custom ADU plan set at a fraction of typical architect fees.
Start My Design →Run your ADU numbers
Get a location-adjusted estimate for your ADU build — instant PDF.
Get Cost Report →What It Actually Costs to Build an ADU
ADUs cost more per square foot than a main house — they carry a full kitchen, bath and utilities in a small footprint — but the total is small and the return is high. Costs swing with type: a garage conversion is cheapest, a detached new build the most. Knowing your real number before you design keeps the project profitable.
A location-adjusted cost report prices your ADU build by area and type, so you can see how size, utilities and finish level change your cost per square foot and your payback.
Recommended Tools and Reports
Custom House Plan
A designer turns your style, size and must-have rooms into a complete plan set — from $499.
Design My Plan →Frequently Asked Questions
How much does it cost to build an ADU in 2026?
Most ADUs run roughly $200 to $400 per square foot to build — higher per foot than a main house because a full kitchen, bath and utilities are packed into a small footprint. A garage conversion is the cheapest path; a detached new-build ADU costs the most. On a 600–800 sq ft unit that typically lands in the low-to-mid six figures, and a location-adjusted cost report prices your specific area.
Can I get an ADU plan designed for my exact lot and city rules?
Yes — that is what our Design Your Dream Home service does. Give us your lot dimensions, setbacks, goal and jurisdiction and a designer prepares a complete ADU plan set from $499, sized to your local height and area limits, typically in 5–7 business days with a free revision round.
What is the difference between an ADU and a JADU?
An ADU (accessory dwelling unit) is a separate living unit — detached, attached or a garage conversion — with its own kitchen and bath. A JADU (junior ADU) is a smaller unit, often under 500 sq ft, created within the existing home’s walls, sometimes sharing some facilities. JADUs are usually cheaper and faster to permit, which the plan can be designed around.
Is building an ADU worth it?
For many homeowners, yes — an ADU can generate rental income, house family affordably and add resale value, often with a strong return relative to its cost. The math depends on your local rents, build cost and rules, so it is worth running a cost estimate and designing an efficient, permittable plan before committing.
Related House Plan Collections
Custom plans from $499 · 5–7 day delivery
Design a Home That Fits You — Not the Other Way Around
Tell us your style, size, rooms and lot. A real designer prepares your complete, print-ready plan set — made only for you.