How We Calculate Costs

The low / mid / high method

Real-world project prices are a range, not a single number, so we never report just one figure. Each calculator returns a low, mid, and high estimate, and splits the total into materials and labor wherever both apply. The low end reflects builder-grade materials and competitive bids; the mid is the most common outcome for a typical project; the high reflects premium materials, difficult access, or higher-cost labor markets. We compute totals from per-unit costs (per square foot, per linear foot, per fixture, or per item) multiplied by the quantities you enter — the same unit-cost approach professional estimators use — rather than from a single averaged lump sum.

Where our cost data comes from

We anchor unit costs to current published ranges from recognized industry sources, then cross-check them against retail pricing. Each calculator lists the specific sources behind its numbers at the bottom of the page. Across the site, our primary references include:

• U.S. Bureau of Labor Statistics (BLS) — wage and producer-price data that informs the labor share of each estimate.
• Major home-improvement retailers(e.g. Home Depot, Lowe's) — current retail pricing for materials, checked periodically.
• Published industry cost ranges (e.g. Fixr, HomeAdvisor/Angi cost guides) — for cross-referencing typical installed prices by project type.
• Trade associations & manufacturer guidelines — for project-specific standards, material specs, and sizing rules (for example, salt-chlorinator targets or septic sizing).

We do not copy figures from competitors without checking them against a primary or retail source, and we cite the sources used on each calculator page so you can verify them yourself.

Adjusting for your state

Use the Location selector on any calculator to adjust the estimate for your state. We apply a regional cost index that scales the two parts of a project differently: laboris adjusted by each state's construction wages relative to the national average — derived from U.S. Bureau of Labor Statistics wage data for the core building trades (carpenters, electricians, plumbers, and laborers) — while materials, which are largely commodity-priced and shipped nationally, move on a tighter band. So a project in Mississippi or Arkansas reads roughly 15–20% below the national average, while Hawaii, Massachusetts, or California read 10–20% above.

This is a state-level approximation, not ZIP-precise pricing — a pricey metro can sit above its state's figure. It gets you a realistic local range to plan and compare quotes against.

What our estimates include — and exclude

Why your actual cost may differ

Our estimates reflect current U.S. industry ranges. Your real price depends heavily on where you live (labor rates in a major metro can run 15–25% above the national average), the season, how busy local contractors are, the condition of the existing structure, and the specific materials you choose. Treat the result as a planning range to budget with and to judge quotes against — not as a binding price. We always recommend getting at least three written quotes from licensed local professionals before committing.

Keeping the data current

Construction prices move, so we review our cost inputs on a regular schedule and update them when sources show a meaningful shift. The most recent review date is shown above and on each calculator. If you spot a number that looks off, please tell us — accountability is part of the method.

Found an error or have better data? Report a data issue.