Every number needs a reason.
Barndo Planner is an editable planning model. It separates a project into useful cost categories so you can replace assumptions with local, scope-matched quotes.
The starting rates are editorial planning allowances. They are not measured national averages, a local price index, current supplier quotes, or a prediction of your final contract price. Published sources inform scope boundaries; they do not substantiate each rate below as a market price.
What this model is designed for
- Single-story, simple rectangular new build on a slab. No basement, second floor, conversion, unusual spans or engineered site remediation.
- USD planning allowances including trade labor. Rates are editorial assumptions, not live bids, nationwide averages or measured local prices.
- Living space is fully conditioned; the shop is unconditioned. A covered porch includes its own slab and roof and is excluded from enclosed area.
- Local multiplier adjusts modeled building work only. Fixed site/soft allowances, land and custom overrides do not change with this multiplier.
- Low and high are scope/price stress scenarios; they are not probabilities, guarantees or a confidence interval. Each includes the selected contingency reserve.
- Financing interest and fees, carrying costs, furnishings, solar, pools, extensive landscaping and specialty equipment are excluded unless entered in Other project costs.
- An override replaces the whole line and preserves that line’s low/high uncertainty. Confirm bundled quotes do not duplicate other lines or builder overhead.
The calculation, in order
- Add conditioned living and unconditioned shop area for the enclosed shell and slab. Porch is separate.
- Calculate each modeled building allowance using its area, fixed equipment amount, finish selection and your local multiplier.
- Add your fixed site, access, utilities, permits, design and other-cost allowances. These do not use the local multiplier.
- Apply a separate 15% builder-management allowance to building and site work, unless you choose owner management or override the fee. All trade labor remains in either mode.
- Apply your contingency percentage to all non-land work, fees and management.
- Add selected land acquisition costs once, with no builder markup or contingency.
Starting rates you can inspect
All area-based amounts below use the simple-footprint assumptions. These are whole-category planning amounts including ordinary trade labor. They are not a supplier’s unit-price schedule.
| Category | Starting formula before local multiplier |
|---|---|
| Shell & erection | $44 × enclosed sq ft |
| Slab & foundation | $14 × enclosed sq ft |
| Windows & doors | $10 × living + $4 × shop |
| Insulation & air sealing | $9 × living sq ft |
| Interior build-out | $40 simple / $56 standard / $85 premium × living sq ft |
| Electrical | $11 × living + $4 × shop |
| Plumbing & fixtures | ($8,000 + $5 × living sq ft) × fixture factor (0.9 / 1.0 / 1.3) |
| HVAC & ventilation | $4,500 + $7 × living sq ft |
| Covered porch including slab | $42 × porch sq ft |
| Temporary services & cleanup | $4,500 fixed base × local multiplier |
How low and high scenarios work
The model applies category-specific low and high factors to show exposure to incomplete scope and price assumptions. Each total combines all corresponding factors in one scenario; it does not assume statistical independence. The factors are planning stress tests, not probabilities. They do not come from a statistical dataset.
| Category | Low multiplier | High multiplier |
|---|---|---|
| Shell | 0.80× | 1.30× |
| Foundation, plumbing, HVAC | 0.80× | 1.40× |
| Openings, insulation, interior, electrical, porch | 0.80× | 1.35× |
| Site preparation & utilities | 0.60× | 1.80× |
| Driveway | 0.65× | 1.60× |
| Permits, design, temporary services | 0.75× | 1.50× |
| Other user-entered costs | 0.80× | 1.50× |
| Management & contingency | Recalculate from each scenario’s eligible subtotal. An overridden management fee uses 0.90× / 1.20×. | |
| Land | 1.00× | 1.00× |
A quoted whole-line override replaces the base amount but retains the line’s uncertainty factors. It is still a planning allowance: the model does not assume the quote is fixed, complete, current or contractually guaranteed.
The complete example scope
The default example uses 1,800 living sq ft, a 600 sq ft unconditioned shop, a 240 sq ft porch, standard finishes and builder coordination. It excludes buying land. The middle scenario is $529,635, including reserve. This is arithmetic from the assumptions, not an observed price for a home.
Shell & erection — $105,600
Structure, roof, siding, erection and standard delivery/tax allowance for enclosed space. Excludes slab, openings, insulation, interior and porch.
Slab & foundation — $33,600
One slab-on-grade foundation for living + shop. Footings, ordinary reinforcement, vapor control and slab labor included; major soil remediation excluded. Porch slab is in the porch line.
Windows & exterior doors — $20,400
Separate allowances for residential windows/doors and basic shop doors. Verify exact quantities and overhead-door sizes.
Insulation & air sealing — $16,200
Conditioned living area only. Confirm climate-specific assembly, moisture control and thermal bridging with the designer. Shop remains unconditioned.
Interior build-out & finishes — $100,800
Interior framing, drywall, paint, floors, cabinets, counters, trim and appliance allowance. Plumbing fixtures are in plumbing; electrical and HVAC are separate.
Electrical & lighting — $22,200
In-building wiring, standard fixtures and basic shop power. Utility service extension is in utilities. Specialty workshop equipment or EV upgrades need quotes.
Plumbing & fixtures — $17,000
Interior plumbing, water heater and ordinary kitchen/bath fixtures. Assumes roughly two bathrooms; well, septic or municipal connections belong in utilities.
Heating, cooling & ventilation — $17,100
Conditioned living space only, including a fixed equipment allowance. Shop heating/cooling and specialty filtration are excluded.
Covered porch — $10,080
Porch structure, roof, slab and basic finish, counted once here. Excludes outdoor kitchen, screening and elaborate decking.
Site preparation & drainage — $15,000
Your fixed local allowance for clearing, grading and normal drainage. Separate from land, the building slab and driveway. No automatic location multiplier.
Well / septic / utility connections — $20,000
Your combined allowance for the utilities your parcel requires: power extension, water and wastewater. Use municipal connections OR well/septic, as appropriate.
Driveway & site access — $8,000
Your allowance for construction access and a finished driveway. Verify length, surfacing, culverts and delivery access.
Permits & impact fees — $5,000
Your local permit and impact-fee allowance. Utility connection fees should be placed in utilities only.
Plans, engineering & surveys — $6,500
Your allowance for architectural plans, structural/site engineering, survey and soil testing. Remove any services already included elsewhere.
Temporary services & cleanup — $4,500
Portable toilet, temporary power/water, dumpsters and final construction cleanup. Long-duration rentals or remote delivery premiums need separate pricing.
Other project costs — $0
Your fixed allowance for applicable costs outside the other lines: financing/carrying costs, furnishings, landscaping, solar or specialty equipment. Identify the scope in your project notes; no automatic local multiplier or builder markup.
Builder management & overhead — $58,572
15% planning allowance on building and site work for general-contractor coordination, overhead and profit. Excludes permits, design, contingency and land. Remove this line if your whole-line bids already include this fee.
Contingency reserve — $69,083
15% of all non-land work, fees and management. A separate reserve in each scenario, not a statistical confidence interval.
Land purchase allowance — $0
Excluded from this project total. Existing land value is not treated as construction savings.
What a price per square foot can hide
The calculator’s building-only ratio divides building-category allowances, including the porch cost, by living plus shop area. It excludes site work, soft costs, management, contingency and land. A builder may use living area alone or include different scope. Match the numerator and the area before comparing any two ratios.
Budget workbook formulas
The workbook exports a snapshot of your scenarios, a checklist, assumptions and sources. The Budget sheet lets you edit base allowances and enter accepted quotes and amounts paid. Its forecast uses an accepted quote when entered, otherwise the planning allowance, and never drops below money already paid. A numeric zero quote is different from an empty cell.
The workbook is a planning and tracking aid. A paid-to-date amount is not the cost to complete the work. Keep builder markups, change orders, held-back payments and excluded scope consistent when entering new numbers.
Sources and their limits
Hansen Pole Buildings planning guide
Separate the kit, erection, slab, utilities and finishes; confirm parcel and design requirements. Accessed 2026-09-24.
DC Structures: Pocatello kit scope
A material package can bundle windows, doors and interior framing while excluding foundation, site work, installation and mechanical systems. Allocate bundled quotes across overlapping categories once. Accessed 2026-09-24.
Barns & Barndos: published 2026 pricing
One supplier distinguishes materials-only kit prices from a completed build; its prices are not nationwide averages. Accessed 2026-09-24.
NAHB: Cost of Constructing a Home, 2024
Broad construction categories and survey limitations. This survey is not a barndominium or state-level cost dataset. Accessed 2026-09-24.
Make the estimate more useful
Confirm your site and utilities first. Share one set of drawings and specifications with bidders, compare included scope, then replace the broad allowances. If a single price includes several categories, allocate it once and remove overlapping estimates.
Make the numbers your own ↗