Our calculator starts from a state cost per square foot for a standard stick-built home, then adjusts for house type, finish level, stories and the options you choose, and adds permits, plans and a contingency. Each step is listed below so you can check every number.
1. State base rate
Each state’s base rate is its estimated total for a 2,000 sq ft home from Today’s Homeowner data, published by Autodesk in 2026, divided by 2,000. Rates range from $143.50 per sq ft (Mississippi) to $215.50 (Hawaii). We use $166 per sq ft as the US reference rate. These are statewide averages; costs in a given city or county can be well above or below them.
2. Adjustments to the core build cost
Core build cost = square feet × state rate × finish factor × house-type factor × stories factor.
| Setting | Factor |
|---|---|
| Finish: basic / standard / premium / luxury | 0.82 / 1.00 / 1.35 / 1.90 |
| Stories: 1 / 2 / 3 | 1.00 / 0.94 / 0.97 |
| House type | 0.32 (barndominium shell) to 1.60 (tiny house); see house types |
The finish, stories and house-type factors are our own estimates, informed by the published cost ranges cited on each page. They are not survey results.
3. Options added on top
| Option | How it is priced |
|---|---|
| Garage (default 2-car attached) | 270 sq ft per bay × $62 per sq ft, scaled by the state rate; detached adds 18% |
| Bathrooms above or below the typical number for the size | $24,000 per bathroom, scaled by finish and state |
| Crawlspace / unfinished basement / finished basement | $9 / $32 / $68 per sq ft of footprint, scaled by state (finished also by finish level) |
| Deck or porch, fireplace | $16,000 and $7,000, scaled by state |
| Metal / tile roof upgrade | $5 / $8 per sq ft of roof area (footprint × 1.18), scaled by state |
| Fiber cement / brick / stone exterior | $3.50 / $10 / $16 per sq ft of wall area (0.95 × floor area), scaled by state |
| Heat pump / geothermal | $4,500 / $26,000, scaled by state |
| Upgraded / chef’s kitchen | $22,000 / $58,000, scaled by state |
| Solar panels | $9 per sq ft of home, capped at $40,000 |
4. Soft costs and site costs
| Item | How it is priced |
|---|---|
| Permits, inspections and impact fees | $20,267 (NAHB 2024: permit fees, impact fees and water and sewer fees), scaled by home size and state |
| House plans | stock plans, $1,500 + $0.70 per sq ft, capped at $4,000; or a custom architect at about 8% of build cost |
| Private well, septic system, lot clearing | $16,000, $12,000 and $7,000 when selected |
| Contingency | 10% by default, adjustable |
| Land | only if you enter a land cost |
5. The range
The most likely total is shown with a range of 14% below to 18% above, because real bids vary with local labor, site conditions and design details. The upper side is wider because overruns are more common than savings.
6. Stage breakdown and build time
The stage chart splits the build cost using NAHB’s 2024 national shares: site work 7.6%, foundation 10.5%, framing 16.6%, exterior 13.4%, major systems 19.2%, interior finishes 24.1%, final steps 6.5% and other 2.1%. Build time is our estimate based on size and finish level, anchored to U.S. Census Bureau data showing an average of 7.6 months from start to completion in 2024.
Why the calculator total is higher than the per-sq-ft tables
Tables on our guides show construction cost only (size × rate). The calculator adds a garage, permits and fees, plans and a 10% contingency by default, so its total is usually higher. Turn options off in the detailed view to match a table figure.
How we choose and update sources
We prefer government data (U.S. Census Bureau, USDA) and industry surveys (NAHB), then established cost guides. Every page lists its sources with dates, and we flag older figures. We review figures when new data is published.
Sources
- Autodesk: How much does it cost to build a house in 2026? (state totals for a 2,000 sq ft home, based on Today’s Homeowner data; the $166/sq ft US median used on this site)
- NAHB: Cost of Constructing a Home in 2024
- NAHB: Single-family homes are built faster in 2024 (U.S. Census Bureau)