Pricing Methodology
Prices are the most sensitive part of any cost tool, and the easiest place for a website to mislead its readers. This page explains exactly how we treat the numbers in our calculators, how we label their origin, and why the defaults you see are starting points to be edited — not authoritative quotes.
The five price categories we keep separate
Not all prices are equal. A figure verified from a documented source is very different from a placeholder we chose to demonstrate a formula. We classify every price into one of five categories and never mix them invisibly:
- Verified-sourced — a figure traced to a documented, identifiable source, with a date and a reference.
- Retailer-product — a price observed from a specific product listing at a retailer at a point in time.
- Contractor-quote — a figure representing what a contractor quoted for a defined scope of work.
- User-entered — a price you type into the calculator. This always takes precedence over our defaults.
- Educational-demonstration — a reasonable placeholder we ship so the calculator produces a sensible example. It illustrates the formula; it does not assert a market rate.
Default prices are educational-demonstration assumptions
This is the most important thing to understand: unless a specific field is explicitly labeled otherwise, the prices that ship as defaults in our calculators are editable educational-demonstration assumptions. They are not verified national averages, and they are not a prediction of what you will pay. They exist so the tool works out of the box and so you can see how changing an input changes the result.
Because every default is editable, the right way to use our calculators is to replace our assumptions with real local prices — a contractor’s quote, a retailer’s current price, or your supplier’s rate. The more of your own numbers you enter, the more useful the estimate becomes.
Freshness: last verified, source, and revision
Prices change over time, so we track freshness for data we present as verified. Where applicable we record:
- Last verified — when the figure was most recently checked.
- Source — where the figure came from, so it can be independently reviewed.
- Revision — a version marker so a given data set produces reproducible results.
When data becomes stale, we flag it and may disable or down-weight it rather than quietly present outdated numbers as current. Our editorial process for dating and reviewing prices is described in our editorial policy.
Location does not equal a local quote
Some tools let you enter a ZIP code or state. This can help frame a rough regional context, but it does not produce a precise local quote. Labor rates, permit costs, material availability, and site conditions vary street by street, not just state by state. Treat any location-adjusted number as a planning aid, never as a bid.
The bottom line
Our calculators are transparent, deterministic, and honest about their inputs. For a real price, get written quotes from licensed local professionals. For how we avoid fabricated averages and credentials, see our editorial policy; for the limits of our estimates, see our terms of use.