eCPMs

eCPM stands for effective cost per mille, with “mille” meaning thousand. It is a metric used in digital advertising to measure the revenue earned per 1,000 impressions. By converting revenue from different pricing models into a per-thousand figure, eCPM allows publishers and advertisers to compare performance across formats, networks, and campaigns on a common scale.

The standard formula is eCPM = (total revenue / total impressions) × 1000. For a publisher evaluating overall performance, total revenue is the money earned from all demand sources and total impressions are all served ad impressions. For a specific demand source, eCPM can be calculated as revenue from that source divided by impressions served to it, then multiplied by 1000.

eCPM is used to assess monetization effectiveness, plan strategy, and benchmark inventory. A higher eCPM indicates more revenue per impression, but it must be interpreted alongside fill rate and overall revenue. Changes in eCPM can result from higher bids, better targeting, more competitive demand, or shifts in format mix (for example, video typically yields higher eCPMs than display).

Several factors influence eCPM, including ad format, creative quality, audience characteristics, geography, time of day, and seasonality. Optimization tactics include increasing fill rate, diversifying demand sources, adjusting floor prices, improving targeting and creative relevance, and testing new formats.

Limitations include that eCPM does not reflect costs or profitability, may be affected by impression quality or inventory mix, and can be distorted by non-human traffic or fraud. It is most meaningful when used alongside other metrics such as total revenue, impressions, and fill rate.