Where Every Number on This Site Comes From

Four sources, two labelled assumptions, and a list of known gaps.

Every number on this site comes from one of four places. This page lists them so you can check the work.

1. Federal wage data

Labor is adjusted using U.S. Bureau of Labor Statistics OEWS medians for Roofers (SOC 47-2181) and Construction Laborers (SOC 47-2061), for all 51 states. The data is public domain. We compute a national baseline as the employment-weighted mean of the state medians, then divide each state median by that baseline to get the multiplier used on every calculator.

That produces multipliers from 0.79 to 1.40 for roofers. The method is reproducible: the weighted mean and the division are both shown in the analysis pieces.

2. Published cost ranges

Material and installed-cost ranges come from published 2026 cost guides and are cited on the page that uses them, with a retrieval date. Where two sources disagree we carry the overlap rather than picking the more flattering number.

3. Our own model

Two things on this site are our modelling choices rather than published figures: the material-versus-labor split for each trade, and the fixed cost per project. Both are labelled as assumptions in the sentence that uses them, not buried in a footnote.

Fixed costs are $650 for a roof, $1,400 for a kitchen, $600 for a bathroom, $250 for flooring, $300 for painting and $280 for a fence. They are planning assumptions.

4. Geometry

Roof area multipliers are exact. Pitch, area and square conversions can be checked with a calculator and are not estimates.

What we do not have

No state-level material pricing. No city-level data of any kind. No permit cost database. No survey of actual invoices. Those gaps are stated on the pages where they matter rather than filled with invented precision.

How to check us

Pick any state page, multiply the labor line by the multiplier shown in the table, and see if you get the total. If you do not, write to [email protected].

Updated October 2026