How Price of Parts works
Price of Parts observes seller listings for exact industrial catalog numbers and publishes the price range, median and seller count for each part — refreshed monthly. This page documents how the index is built and what is filtered out.
Catalog numbers are discovered across multiple independent public catalog sources, so no single seller's assortment defines the index. Each candidate number is verified against real buyer search demand: numbers nobody looks for are dropped, which also removes most extraction noise. For every remaining number we observe the listings sellers publish to public marketplaces and product feeds — a channel that includes specialist trade houses that do not allow conventional crawling. The specific sources, collection methods and matching implementation are proprietary and not disclosed.
Exact configuration match
1756-EN2T is a substring of six sibling variants, and ACS580-01-430A-4+J400 is a different configuration than the bare number. A listing counts only if it names the exact catalog number as a complete token, with no option codes attached. On the 1756-EN2T this cut the apparent spread from 9.9× to 1.5×.
Accessories, services & clones
A $14.50 battery for the 1785-L26B carries the same catalog number as the $6,901 processor, and a "relay for 440R-S12R2" is a compatible clone, not the OEM part. Batteries, keypads, covers, repair services, multi-unit lots and for-listings are excluded.
Placeholder prices
One seller listed over a thousand parts at $0.01. Sellers whose listings are 20% or more placeholder prices are excluded entirely; prices below 25% of a part's median are excluded individually.
Seller deduplication
Some sellers publish up to seven listings for one number, and many operate marketplace storefronts under a second name. Storefront mirrors are merged and each seller counts once, at its lowest listed price.
Outlier removal
Prices more than three median absolute deviations from the part's median are excluded — a $37,505 listing on a $575-median part does not represent the market.
Manufacturer verification
The manufacturer is verified against seller titles by majority vote. Ambiguous product matches — one token, multiple distinct products — are not published.
| Median asking price | ≥ $100 |
| Sellers | ≥ 5 |
| Specialist (non-marketplace) sellers | ≥ 3 |
| Product match | exact and unambiguous |
Roughly 84% of listings do not state condition; where a listing is identifiably used or refurbished it is labeled, and unstated condition is shown as unstated — not assumed new. Hardware series revisions of the same catalog number (Ser. A/B/C) are currently combined on one page; about a third of parts show more than one series in the market, and per-series separation is on the roadmap. Stock levels and lead times are not yet tracked. Prices are published asking prices from US seller listings; shipping, taxes and negotiated trade pricing are not included. We observe seller listings — we do not know negotiated pricing.