Cost to Build a House Estimator

Cost to Build a House Estimator — guide & how to use

Planning-grade rough estimate, not a bid. This is designed to size a construction loan and sanity-check builder quotes — it does not replace a line-item estimate from a licensed builder. The output is intentionally a low–high range; a single firm number would be misleading. It excludes land (unless toggled on), finished basement/bonus space, landscaping, pools, driveways beyond standard, furniture, construction-loan interest, and significant change orders. All math runs privately in your browser.

What it does

This estimator turns your finished square footage, finish level, number of stories, foundation, region, and site difficulty into a low–high cost-to-build range with an itemized breakdown: core construction, foundation adder, site work, soft costs, and an effective per-square-foot figure. Optionally add land for a total-project number.

How to use it

1. Enter your finished living area in sq ft (exclude garage, porch, unfinished basement).
2. Pick your finish level, stories, foundation, region, and site difficulty.
3. Optionally toggle land on and enter your lot price for a total-project figure.
4. Leave soft costs on unless you already have plans and permits handled.
5. Read the build range, the $/sq ft, and the breakdown — then compare against the NAHB benchmark chip.

How the math works

1. Base rate band by finish: builder-grade $180–$280, mid-range $200–$300, high-end custom $280–$450 per sq ft (all-in 2025–2026 national bands).
2. Story multiplier on the rate: single-story ×1.12, two-story ×1.00, three+ ×1.05.
3. Region multiplier on the rate (and tear-off-style adders): National 1.00, Midwest 0.90, South 0.92, Northeast 1.18, West 1.15, high-cost metro 1.40.
4. Core construction = adjusted rate × area (slab baseline).
5. Foundation adder charged on the footprint = area ÷ floors: crawl +$3–$6, unfinished basement +$18–$30 per footprint sq ft; slab adds $0.
6. Site work = a single percentage of core construction (5% / 8% / 15%) on each bound.
7. Soft costs (if on) = 10% of the hard-cost low and 15% of the hard-cost high, with an $8,000 permit floor on the low side.
8. Construction total = hard cost + soft cost. Total project adds land only if the toggle is on.

Worked example

The self-test case: 2,600 sq ft, mid-range, two-story, slab, National, Typical (8%) site work, soft costs on:

• Adjusted rate = $200–$300 × 1.00 (stories) × 1.00 (region) = $200–$300/sq ft.
• Core construction = 2,600 × ($200–$300) = $520,000 – $780,000.
• Foundation adder (slab) = $0. Site work (8%) = $41,600 – $62,400.
• Hard subtotal = $561,600 – $842,400.
• Soft costs = max(10% × $561,600, $8,000) – 15% × $842,400 = $56,160 – $126,360.
• Build total ≈ $618,000 – $969,000, or roughly $238 – $373/sq ft effective.

Each displayed dollar figure rounds to the nearest $1,000 and per-sq-ft figures round to the nearest $1; intermediate math uses full precision, so a hand-check may differ by a few dollars. This mid-range 2,600 sq ft result lands near the published all-in bands (≈$0.62M–$0.97M build), which is exactly the spec's self-test target.

Accuracy notes & assumptions

• This is a planning-grade rough estimate, not a bid. It sizes a construction loan and sanity-checks builder quotes; it does not replace a line-item estimate from a licensed builder.
• Per-sq-ft costs vary 2–3x by region, finish, and site conditions. The regional multipliers are coarse indices — a specific zip code can deviate materially. Confirm with 2–3 local builder bids.
• Bands reflect 2025–2026 national data (HomeGuide, Angi, NAHB, Home-Cost) and move with inflation and tariffs. Labor alone is ~35–40% of build cost and is the most volatile input; re-verify figures annually.
• Land is excluded unless toggled on. It is the most common reason per-sq-ft budgets fail and varies from a few thousand to $350k+ per acre.
• Soft costs are a band plus a permit floor. Actual architect (8–15%) and permit/impact fees ($5k–$30k) depend heavily on jurisdiction and plan complexity; a stock plan can cut the architect portion to near zero.
• Foundation, site, and story multipliers are simplifications of real engineering. Soil conditions, water table, slope, and utility distance can swing foundation and site costs far beyond the tier adders shown.
• High-cost metro + high-end custom can exceed $600/sq ft — that's not capped; ultra-custom and metro builds routinely exceed published ranges and require a real builder bid.

Common mistakes this avoids

• Multiplying a single per-sq-ft number by area and treating it as the budget — ignoring the spread and the big exclusions. The range and excluded-items list exist to counter this.
• Forgetting land. Buyers see "$200/sq ft × 2,600 = $520k" and assume that's all-in; land can add six figures.
• Assuming a basement is "free space." An unfinished basement adds ~$18–$30/sq ft of footprint, and finishing it is extra (not included here).
• Believing a single-story is cheaper per sq ft than a two-story — it's the opposite; ranches carry more foundation and roof per sq ft.
• Counting garage, porch, and unfinished areas in "finished square footage," inflating the living-area cost.
• Treating the builder's "sticks and bricks" bid as turnkey — leaving out architect, engineering, permits, site work, driveway, landscaping, and loan interest.
• Using the national average for a high-cost metro (or vice versa). Region is one of the largest swing factors — set it honestly.

Frequently asked questions

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