What this site is — and isn't
Each calculator returns a planning-range estimate, not a contractor bid. A planning range gives you a low-to-high band wide enough to absorb regional variation, scope uncertainty, and contractor-to-contractor pricing differences. It is a starting point for budgeting and a sanity check on quotes — not a replacement for a real contractor walkthrough.
We always recommend collecting 2-3 local quotes from licensed contractors before purchasing. The calculator tells you whether those quotes land in a reasonable band; it does not tell you which contractor to pick.
Where the numbers come from
For every calculator, the rate ranges are independently derived planning ranges informed by:
- Public material pricing — manufacturer MSRP (Velux, Therma-Tru, Trex, Generac, ChargePoint, Tesla, Heat & Glo, etc.), retail aggregators (HomeGuide, HomeAdvisor, Homewyse, ConcreteNetwork), and trade-association data (NRMCA for concrete, NWFA for hardwood, ARMA for roofing).
- Public wage data — BLS Occupational Employment and Wage Statistics by trade (Carpenters 47-2031, Electricians 47-2111, Plumbers 47-2152, Roofers 47-2181, Brickmasons 47-2021, etc.).
- Federal energy / efficiency program data — DOE / EnergyStar (HVAC, water heaters, insulation), NREL (residential solar benchmark), IRS publications for residential tax credits.
- Licensed cost-estimating references — used internally as one of several benchmark anchors for sanity-checking ranges. We do not republish, copy, or quote tables, rows, or descriptions from any licensed reference.
Where multiple sources disagree, we widen the planning band rather than picking a single number.
Labor model: per-unit + crew-rate sanity check
Most calculators use per-unit installed rates (per square foot of drywall hung, per linear foot of fence, per opening for a door, etc.). These are how residential contractors quote in practice.
Behind those per-unit rates we apply a loaded crew-rate sanity check derived from BLS OEWS wage data plus payroll burden, crew composition, overhead, and profit. If a per-unit rate would imply a crew-hour billing rate outside a reasonable band ($55-$160/crew-hr depending on trade), the rate gets revisited.
A few calculators that have crew-hour-driven scope at their core (concrete-slab, drywall) compute crew hours explicitly from a production rate (sq ft per crew-hour) and surface that as a line item.
Location adjustment: ZIP planning zones
The ZIP / planning zone input uses the first 3 digits of a ZIP code to look up a regional planning index with separate material, labor, and equipment multipliers. This is a planning approximation, not exact local pricing:
- Curated metro entries (e.g. San Francisco 941, NYC Manhattan 100-102) carry distinct multipliers reflecting that metro's wage and material premium.
- ZIP prefixes outside the curated list fall back to the state average via a USPS prefix → state lookup.
- If no ZIP is entered, the user-selected state's multipliers apply.
- If neither ZIP nor state is selected, the national-average baseline (1.00 / 1.00 / 1.00) applies.
The multipliers are rounded to the nearest 5% and reduced from any source dataset. The result is a planning index informed by wage and material signals plus reduced regional benchmarks — not a reproduction of any cost-book table.
Markup & how totals add up
For "Pro installed" mode the calculator stacks line items (material, labor, equipment, permits) and adds an 18-30% contractor overhead-and-profit markup to the markup-eligible portion of the subtotal.
Lines that already include contractor profit (CSV basis = "installed") and jurisdictional flat fees (permits) are excluded from the markup base. They pass through at their stated price. This avoids double-counting profit on subcontracted work.
For "DIY materials only" mode, labor and markup are excluded; you see materials plus a small DIY tool-rental allowance.
Federal tax credits
Several calculators flag eligibility for federal residential energy / efficiency credits — Section 25D (residential clean energy), Section 25C (energy-efficient home improvement), and Section 30C (alternative-fuel-vehicle-refueling property).
The rates and expiration dates of these credits were modified by recent legislation (the Inflation Reduction Act, then the 2025 OBBB Act). The calculators flag eligibility only — they do not bake an after-credit number into the displayed total.
Always verify the current rate and your eligibility on the appropriate IRS form (5695 for 25D / 25C, 8911 for 30C) before relying on a credit for project planning. We are not a tax service; consult a tax advisor for your specific situation.
What the calculator can't see
Some real costs only show up at a site visit and aren't in our planning range:
- Hidden conditions — rotten framing behind drywall or fascia, asbestos in old vinyl flooring or pipe insulation, knob-and-tube wiring, water in a basement that needed a sump three years ago.
- Code triggers — adding a circuit may require a panel upgrade; adding bath square footage may require a bigger hot-water heater; replacing a window may require a tempered-glass code-out.
- HOA / historic / coastal — design review, hurricane-impact requirements, preservation matching all add cost.
- Access — anything multi-story, far from a driveway, or in a tight urban lot adds 10-30%.
- Demolition discovery — what's under the surface usually only reveals itself after demo.
- Schedule pressure — same-week emergency calls cost more than a job that can wait a month.
If the quote you got is outside the planning range
Use the Bid check panel on each calculator. Enter the contractor's quoted total and what it includes; the panel flags whether the quote is in band, low (suspicious — verify scope completeness), or high (verify regional / scope reasons).
Quotes 10% below our low end are often missing line items, materials below spec, or unlicensed work. Quotes more than 25% above our high end are usually in a tight market, complex access, premium materials, or scope creep that the calculator doesn't capture. Both are worth a conversation with the contractor.
Updates & corrections
Calculators are revisited annually for the new construction year. Each rate row in the underlying CSVs carries a lastUpdated date. Major scope additions (new categories, new tax-credit changes, new code-required materials) trigger an off-cycle update.
If you've found a number that looks wrong against your local market, send a note describing the project and the quote you got. Real-world quotes drive recalibration.
Last updated: May 2026.
