Methodology

CurbMark's estimates are built from national-average base rates, adjusted for the specific project, quantity, quality tier, home age, and location you tell it about. This page explains where those numbers come from and how the math works, so you know what you're looking at.

Where the base rates come from

Every project type's base cost is sourced from current public cost guides — primarily HomeAdvisor/Angi and Homewyse — cross-checked against typical ranges reported by contractors and, for Deck/Patio specifically, the Zonda/Remodeling Magazine Cost vs. Value report's whole-project figures (generic "$/sq ft" deck quotes consistently understate real installed cost, since they tend to price the decking material alone and miss footings, railings, stairs, and permits).

These are consumer cost-guide aggregates, not a licensed RSMeans dataset or a formal contractor takeoff. They're meant to give you a real, defensible range to start a conversation with — not a substitute for an actual quote.

How the calculation works

For most project types, the estimate is built as:

base rate × quantity ratio × quality tier × home age × regional adjustment

• Base rate — the national-average cost for that project at its typical default size (for example, a 1,800 sq ft roof, or 10 windows).
• Quantity ratio — scales the base rate up or down for the actual size or count you enter.
• Quality tier — Budget, Mid, or Luxury, where Mid is the baseline (×1.0), Budget is roughly ×0.72, and Luxury is roughly ×1.65. Some project types (like Roof or Windows) skip this control entirely because the material choice itself already is the quality ladder — stacking a separate tier on top would be redundant.
• Home age — homes built before 1970 carry a modest surcharge (roughly ×1.15) to account for the higher odds of surprises behind the walls; 1970s–1990s homes carry a smaller one (roughly ×1.05); 2000s-or-newer homes use the baseline.
• Regional adjustment — your ZIP code is resolved to a state, and each state carries its own cost multiplier relative to the national average. This blends two federal data sources: the Bureau of Economic Analysis's Regional Price Parities (a broad cost-of-living index across goods, housing, and services) and the Bureau of Labor Statistics' Quarterly Census of Employment and Wages for the construction industry specifically (which swings harder by state than general cost of living does, since it's wages alone). The two are weighted by how much of a typical project's cost is actually labor versus materials, so a state with unusually expensive construction labor but average everyday prices — or vice versa — lands somewhere honest between the two, not wherever a single index happens to say.

Kitchen and Bathroom work differently: instead of one scope choice, each individual component (cabinets, countertops, appliances, and so on) has its own base rate, and you only pay for what you actually mark as being replaced.

Why you see a range, not one number

The "Mid" figure is the calculation above. "Low" and "High" widen that by roughly 25% below and 32% above, reflecting the real spread contractors quote for the same job depending on who you hire, material availability, and site conditions.

What this isn't

CurbMark doesn't know your specific contractor, your home's actual condition, local permitting quirks, or anything a real inspection would surface. Treat the number as a well-informed starting point, not a quote — always get multiple written bids from licensed, insured contractors before making a financial decision.

This tool also isn't meant to be used by a contractor to set or justify their price. It's here to help you understand a possible ballpark before you start a conversation, not to anchor one. See our Terms of Service for the full disclaimer.

Keeping this current

Construction costs move. We aim to re-check the underlying rate data periodically against current cost guides rather than letting it go stale. The regional adjustment updates on its sources' own release schedules — BEA publishes revised Regional Price Parities annually, typically in February, and BLS publishes revised QCEW wage data annually each fall — if you notice a number that looks off for your area, we'd genuinely like to hear about it at hello@curbmark.app.