Austin ADU Cost
What an ADU actually costs to build in Austin.
Real numbers from our plan catalog, broken out by size — plus what the figure covers, and the things on your lot that move it.
- Austin, TXLocal design + build
- Make it yoursPick a plan or customize
- 293+ plansPre-designed catalog
- WarrantiedStandard on every build
What does an ADU cost per square foot in Austin?
Across the 293 plans in our catalog, estimates land between $290 and $537 per square foot, with a midpoint around $311. Two things drive that spread. Size is one: design, permitting and utility work are budgeted per project rather than per square foot, so a smaller build carries the same overhead across less area. What the plan is made of is the other — kitchens and bathrooms cost several times what living space does per foot, so two plans of the same size can land well apart.
| Size (sq ft) | Typical cost | Per sq ft | Plans |
|---|---|---|---|
| Under 500 | $161,000 | $340 | 29 |
| 500 – 749 | $198,000 | $318 | 103 |
| 750 – 999 | $268,000 | $302 | 112 |
| 1,000+ | $314,000 | $293 | 49 |
Median figures across plans from 384 to 1,099 sq ft. Rough estimates for the plans on this site — not prices of ADUs we have built or sold.
What that figure includes
Design
Plan selection or customization, construction drawings, and the engineering the city asks for.
Permits
The Austin submittal, plan-review corrections, and inspections through Certificate of Occupancy.
Utility connections
Running water, wastewater and electric to the new unit — a real line item, and a variable one.
Construction & management
The build itself, plus the project management that keeps one team accountable start to finish.
What moves the number on your lot
These are the things a site visit settles, and the reason we quote a range until we’ve seen the property.
- How far the unit sits from existing water, wastewater and electric — the longest single swing on most lots.
- Site access. A backyard a small excavator cannot reach changes how the work gets done.
- Slope, trees and drainage. Protected trees and steep ground both add design and site work.
- Finish level. The same footprint can be built to very different specifications.
- Whether an existing slab or structure can be reused, as in a garage conversion.
What we've built
A few of our completed projects, paired with the plans they were built from.
How we get to a real number
The estimate above is a starting point. Four steps take it to a figure you can build against.
- 1
Talk
Budget, timeline, and what you want the space to do.
- 2
Site visit
Utilities, access and trees — what the lot actually allows.
- 3
Firm proposal
A plan, a scope and a price, in writing.
- 4
Permit & build
We file the paperwork and run the build.
Cost questions
The ones we're asked most about budget and financing. The full FAQ has the rest.
Can I use a home equity loan to build an ADU?
Yes! Provided you have enough equity to cover at least 80% of the total cost.
Does your ADU service include design/build or construction management services?
Because ADU is a design-build company we can offer services from concept to keys. Wherever you are in the process - whether it be in the design phase or whether your project is permitted and ready for construction - ADU can help you reach your goals with your ADU build.
How long does it take to build?
We're still gathering data points on how quickly we can build adus, but on average 6-9 months.
Want a real number for your lot?
Tell us about your property and what you're planning — we'll come back with what it takes.
Prefer to talk? (512) 331-2238
Take the whole catalog with you
All 293 of our plans — floor plans, sizes, and features — in one PDF.
