Our Data & Methodology
Transparency is the foundation of trust. Here's exactly how we calculate our cost estimates and where our data comes from.
Editorial + Data Verification Checklist
- Research team updates datasets and calculator assumptions (monthly)
- Licensed advisor validates pricing bands and safety guidance
- Editorial desk documents the change log and cites sources
- Production rebuilds the site and spot-checks UI accessibility
See the “Last updated” banner on each page for the most recent pass through this workflow.
Data Sources
Contractor Quotes Database
Our primary data source consists of over 15,000 real contractor quotes collected from across the United States since 2020.
- All data is anonymized and aggregated
- Covers all 50 states and major metropolitan areas
- Updated monthly with new submissions
Industry Cost Indices
We cross-reference our data with established industry cost indices to ensure accuracy and regional adjustments.
- RS Means Construction Data
- Bureau of Labor Statistics
- National Association of Home Builders
Regional Adjustments
We apply location-specific multipliers to account for regional variations in labor and material costs.
- Cost of living indices by metro area
- Local permit and inspection fees
- Regional material price variations
Expert Validation
All calculations are reviewed by licensed professionals to ensure real-world accuracy.
- Licensed general contractors
- Specialty trade professionals
- Construction cost estimators
Our Calculation Process
Data Collection & Anonymization
We collect project quotes from licensed contractors across the United States. All personal and business identifying information is removed, and only project specifications and costs are retained.
Data Points Collected:
- • Project type and scope
- • Materials used and quantities
- • Labor hours and rates
- • Geographic location (metro area)
- • Project complexity factors
- • Permit and inspection costs
Statistical Analysis & Outlier Removal
We apply rigorous statistical methods to identify and remove outliers, ensuring our estimates reflect typical market conditions rather than extreme cases.
Statistical Methods:
- • Interquartile range (IQR) analysis for outlier detection
- • Weighted averages based on project similarity
- • Seasonal adjustment for time-based variations
- • Confidence interval calculations (±15% range)
Regional Calibration
We adjust base estimates using regional cost multipliers to account for local market conditions, labor rates, and material availability.
Regional Factors:
- • San Francisco Bay Area
- • New York City Metro
- • Los Angeles
- • Boston
- • Rural Midwest
- • Small Southern cities
- • Mountain West towns
- • Some Midwest metros
Expert Review & Validation
Before publication, all estimates undergo review by licensed professionals to ensure they align with current market realities and industry standards.
Review Process:
- • Technical accuracy verification
- • Market condition assessment
- • Sanity checks against known project costs
- • Quarterly review and updates
Limitations & Important Notes
What Our Estimates Include & Exclude
✓ Typically Included:
- • Standard materials and labor
- • Basic permits and inspections
- • Standard installation practices
- • Contractor overhead and profit
- • Waste and miscellaneous costs
✗ May Not Include:
- • Extensive site preparation
- • Premium or luxury materials
- • Structural modifications
- • Emergency or rush job premiums
- • Extensive permit complications
Questions About Our Methodology?
We believe in complete transparency. If you have questions about our data sources, calculation methods, or would like to contribute data to improve our estimates, we'd love to hear from you.