MVP estimator
ADU planning range
Use this to pick a next step, not to pretend your lot has been inspected through the screen.
Guide
What homeowners need to know.
Use ranges until the scope is real
A useful estimator names assumptions. A bad estimator spits out a suspiciously exact number before it knows the lot.
Inputs that matter
City, ADU type, square footage, existing garage, drawings, permit status, utilities, finish level, site access, and timeline all change the recommended path.
Output should suggest next step
The right output is not just a number. It should tell the homeowner whether to start with feasibility, permit-ready plans, builder shortlist, or prefab comparison.
Cost table
Use ranges until scope is real.
| Item | Planning range | Why it moves |
|---|---|---|
| Detached ADU planning range | $300k-$600k+ | Use as an early screen until site and utility review. |
| Garage conversion planning range | $120k-$300k+ | Existing structure condition controls the spread. |
| Prefab planning range | $250k-$500k+ | Requires site-work and delivery assumptions. |
Mistakes
Avoid these expensive shortcuts.
- Treating an online estimate as a bid.
- Skipping city and utility inputs.
- Asking for construction quotes before drawings make bids comparable.
FAQ
Fast answers.
Can an ADU calculator give an exact cost?
No. It can give a planning range and identify cost drivers. Exact pricing needs scope, drawings, site review, and provider bids.
Sources