Cost per mille (CPM) is the cost of serving 1,000 ad impressions. It’s a core metric in digital advertising used to measure how efficiently a campaign reaches its intended audience across different platforms and formats.
In B2B marketing, CPM helps marketers evaluate the value of impressions based on audience quality, context, and intent, not just scale. For example, reaching a small, highly specialised audience with purchasing authority often justifies a higher CPM than broad, low-intent traffic.
Analysing CPM alongside downstream metrics like click-through rate (CTR), cost per click (CPC), and cost per lead (CPL) provides a fuller picture of campaign performance, helping teams balance brand visibility with lead generation efficiency.