Cost per Mille is what an ad network charges to deliver 1,000 impressions. 'Mille' is Latin for thousand — the unit is conventional. CPM is the most direct measure of how expensive it is to put a message in front of your audience on a given platform at a given time.
CPM = (Ad Spend / Impressions) × 1000
Why it matters
CPM is the price you pay to reach. Two campaigns can have the same spend but very different reach if one is bidding into a more crowded auction. CPM is also a signal of audience size and competition — narrow audiences and high-intent segments cost more per thousand impressions because more advertisers want them.
Typical ranges
- Meta broad targeting (cold): €5 – €15 CPM in most EU markets
- Meta retargeting: €15 – €40 CPM (smaller audience, higher competition)
- Q4 / Black Friday: CPMs often 1.5× – 2× annual baseline
- TikTok cold: typically lower CPM than Meta but harder conversions
- LinkedIn B2B: €20 – €80 CPM, the highest of the major platforms
Reading CPM movement
If your CPM jumps 30% week-over-week without a creative change, look at audience definition (did Meta widen or narrow?), time of year (Q4, post-iOS), and competing advertisers in your category. CPM is the metric most outside your control — you optimise around it, not against it.