Why these are free
Two reasons, and neither is especially noble.
The first is that I built most of them for myself. Every media audit I run needs the same handful of calculations, and I got tired of rebuilding spreadsheets that lived in one client folder and died there. Putting them on a public page cost me very little beyond writing the explanations properly.
The second is that the industry has a bad habit of gating trivial arithmetic behind a form. A ROAS calculation is division. Asking for a work email address in exchange for it is not lead generation, it is a toll booth on a footpath. If these are useful, use them — and if you later need someone to look at an account properly, you will know where I am.
What you will not find here
No benchmark figures. I am not going to tell you the average CTR in your industry or a typical CPM for your market, because those numbers vary so enormously by format, placement, season and country that publishing one would mislead you more than it would help. Every figure these tools produce is derived from numbers you entered.
No email walls, no results gated behind a sign-up, and no tracking of the values you type. The calculations happen in your browser; nothing is transmitted. The shareable links some tools offer encode your inputs in the URL, so treat those the way you would treat the numbers themselves.
Using these on your own site
Every calculator has an embeddable version with a copy-and-paste snippet on its page. If you teach, run an agency, or are putting together internal training, take them. The only condition is the attribution link already inside the embed, and I will not retroactively add tracking to something you have placed on your site.
What is coming
The list I am working through, roughly in order: a budget pacing tracker, a campaign pre-launch QA checklist, and a UTM builder that enforces a naming convention rather than just concatenating strings. If something you need is missing, tell me — the useful ones have all come from someone asking.
Go deeper: Performance marketing · Marketing analytics · Mentorship · Field notes