400 sq. ft.
$100,000400 sq. ft. × $250. Separate costs and custom selections still need to be priced.
Explore this size ↗A CLEARER LOOK AT THE POSSIBILITIES
What could your
casita cost?
Start at $250 per square foot for every layout. Explore construction cost and the potential resale contribution of new livable space, using your ZIP code, one of 40 featured Arizona market snapshots, or your own home’s price per square foot.
Explore cost + potential equity ↓BUILD COST + RESALE POTENTIAL
Move the bar.
See the possibilities.
400 sq. ft.1,800 sq. ft.
Type your own ZIP, or explore 40 featured Arizona ZIP codes across the Phoenix area, Prescott, Sedona and Tucson.
Paradise Valley: a dated local sale benchmark is available below.
85253 market snapshot
3 months ending September 2026. All-home-type median sale price: $762/sq. ft. Checked October 25, 2026.
View Redfin market source ↗You can use your home’s expected sale price divided by its livable square footage. ZIP boundaries can include multiple communities.
See the assumptions and calculation
Added resale value = casita area × your selected home-sale price per square foot, at 100%. Potential equity = added resale value − starting construction estimate − additional costs you enter.
This is a resale scenario that assumes the new livable space contributes at the same $/sq. ft. as the selected benchmark. ZIP medians describe sold homes; they do not establish what a specific addition will sell for. Property, finish level and market conditions affect the outcome. The 40 featured ZIP codes are a curated selection of Arizona markets, not a statewide ranking.
Starting construction estimate at $250/sq. ft. Property conditions, design and selections determine the final proposal. Permit fees, required fill, appliances, and other site-specific or optional work are separate. With $0 additional costs, those separate expenses have not been deducted. Financing, holding and selling costs are included only if you enter them.
ONE STARTING RATE. EVERY SIZE.
Starting construction, by size.
1,000 sq. ft.
$250,0001,000 sq. ft. × $250. Separate costs and custom selections still need to be priced.
Explore this size ↗1,800 sq. ft.
$450,0001,800 sq. ft. × $250. Separate costs and custom selections still need to be priced.
Explore this size ↗KNOW WHAT YOU’RE COMPARING
The scope matters as much as the number.
Defined in your construction proposal
- Design and engineering scope
- Standard excavation and grading scope
- Foundation, structure, roof, and building enclosure
- Electrical, plumbing, and heating and cooling
- Interior finishes and specified allowances
- Project coordination and construction completion
Separate or property-specific
- Permit fees and required fill dirt
- Extraordinary underground conditions and hard dig
- Utility distances, service upgrades, or septic work
- Demolition, retaining walls, and unusual access needs
- Concrete pump when required
- Client-supplied appliances, pools, landscaping, and furniture
Your project’s written proposal and agreement control final inclusions, allowances, exclusions, and changes.
MAKE ROOM ON YOUR CALENDAR
Explore a possible timeline.
Choose a start date and adjust each stage to see how the dates connect. These are planning assumptions; your actual schedule is set around the property, approvals and agreement.
- 01 · Design preparedChoose a start date
- 02 · Assumed construction readinessChoose a start date
- 03 · Illustrative completionChoose a start date
Sequential illustration, excluding weekends. Holidays, agency delays, site conditions, changes and any overlap between stages are not modeled. The default construction assumption is 180 business days; it is not a guaranteed completion date.
A FEW GOOD QUESTIONS
How to read the estimate.
What does the $250 per square foot starting price mean?+
Every layout in this collection uses the same $250 per square foot starting construction rate. The final proposal reflects the property, design, utilities and selections. It is not a fixed all-in price.
How is potential equity calculated?+
We multiply the new casita area by 100% of your selected sale price per square foot, then subtract starting construction and the additional costs you enter. You can replace the ZIP benchmark with your own home’s expected sale price per square foot.
Can I enter my own ZIP code?+
Yes. Type any five-digit ZIP code, or choose from 40 featured Arizona markets. A featured ZIP loads its dated benchmark. For another ZIP, your construction estimate still works, and you can enter your own resale price per square foot or continue with construction cost only.
Where do the ZIP values come from?+
The presets use dated Redfin ZIP housing-market snapshots for all-home-type median sale price per square foot. The selected source and observation period appear in the calculator. They are market context for an editable resale scenario, not a live valuation of your property.
Are permit fees and fill dirt included?+
Permit fees and required fill dirt are separate. Utility work, access, underground conditions, premium selections and other project-specific work need to be identified and priced. Enter those costs in the calculator when you have them.
Is everything in the renderings included?+
Renderings show design possibilities. Pools, patios, landscaping, furniture, specialty features and upgraded finishes may be optional or separate. The written proposal determines the construction scope.
LET’S CREATE SOMETHING PERSONAL
Let’s talk about your actual property.
Share your location, your goals, and the space you have in mind. We’ll help define the next step.
Start Planning Or call 602-932-7122