Trust lane
About this site
By Oliver Wakefield-Smith · updated July 2026
The short answer
whatiscpm.com defines one advertising metric properly: what CPM is, how to compute it, and what it currently runs on channels honest enough to have a citable number. It is written and maintained by Oliver Wakefield-Smith, founder of Digital Signet, and it asks nothing from you: no signup, no gated PDF, no cookie-wall theater.
The operating rules
- Numbers carry their papers. Every benchmark renders with its source and retrieval date attached, and the whole set is inspectable in one place: the rate ledger. That page is our answer to the methodology essay; we would rather show receipts than prose.
- No rate gets invented.Most ad channels publish no prices. Where that is true we say so on the channel's own page instead of laundering a number from an undated blog. Thirteen of nineteen rows in the rate table are honest blanks today.
- The calculator does the site's math. Worked examples in the copy are generated by the same arithmetic as the solver, so the prose cannot drift from the tool.
How it is funded, and the bias question
The site is part of a portfolio of free calculators and reference tools built by Digital Signet. No ad platform, agency or vendor pays for placement here, and no benchmark source has a commercial relationship with us. If that ever changes on any page, the page will say so in plain text where the number appears.
Found a stale number?
Benchmarks are reviewed quarterly (July 2026 was the last pass; October 2026 is next). If a figure has aged badly or a channel has started publishing rates we should cover, email oliver@digitalsignet.com with a link to the primary source. Corrections ship faster than features.
Start points: the definition, the FAQ, or the benchmark table.