What value-based bidding means
Value-based bidding is a subset of Google Ads Smart Bidding strategies. Instead of optimizing for the highest possible number of conversions, the way Maximize Conversions or Target CPA do, it optimizes for the highest possible value of those conversions, within a budget or a target return on ad spend (ROAS).
The advertiser assigns a value to each conversion, either dynamic (the actual amount of each sale, for example) or static and different by conversion type (a booked demo is worth more than a downloaded PDF, a qualified lead more than a generic contact form). Google needs at least two distinct conversion values for the system to have anything to distinguish; if every conversion is worth the same, value-based bidding has no new information to optimize on and behaves like a volume-based strategy.
There are two ways to apply it: Maximize Conversion Value, with no efficiency limit, and Target ROAS, which also requires maintaining a minimum return per euro spent. Both are available for Search, Shopping, Video, and Demand Gen campaigns, though the minimum conversion volume requirements vary by campaign type. The dynamic value is calculated from the actual amount of each conversion, while the static value is a fixed number the advertiser sets once per conversion type and that stays the same without a manual update.