CPM

Cpm is an acronym used in several fields, with the most common meanings being cost per mille in advertising, and counts per minute in scientific and clinical measurement. The term may also appear in discussions of CP/M, a historical computer operating system, though that form is usually written CP/M.

In advertising, CPM stands for cost per mille, or cost per thousand impressions. It expresses how much advertisers pay for 1,000 served ad impressions, whether on display, video, or social formats. The CPM rate is used to budget campaigns, compare media plans, and forecast reach. Calculations are straightforward: CPM equals (cost divided by impressions) times 1,000. Higher-quality inventory, targeting, and viewability typically affect the effective CPM.

In measurement, CPM can mean counts per minute, the rate at which events are recorded by a detector such as a radiation counter or gamma camera. It is commonly used in radiological protection, nuclear medicine, and environmental monitoring. Counts are subject to Poisson statistics; background counts must be estimated and subtracted to obtain net activity estimates. Converting CPM to activity units like becquerels requires knowledge of detector efficiency and geometry.

CP/M, standing for Control Program for Microcomputers, is a separate historical operating system from the 1970s and 1980s. It was developed by Gary Kildall of Digital Research and influenced later systems, including early PC-compatible DOS environments. It is generally distinguished from the marketing and measurement meanings of Cpm/CPM by its slash notation and computing context.