Bid eCPM (Effective Cost Per Mille) represents the effective cost per thousand impressions based on a bid. It helps advertisers estimate the potential cost and value of winning a placement in a real-time bidding (RTB) environment.

Bid eCPM is a valuable metric for comparing the cost-efficiency of different ad placements. By optimizing bid eCPM, advertisers can control ad spending while maximizing reach and impression value, improving campaign cost-effectiveness.