An advertising system receives from an advertiser at a social networking system an advertisement request, the advertisement request comprising advertisement content and a specification of a target audience for the advertisement content. The advertising system defines a plurality of bid values for the advertisement request. For each of the plurality of bid values, the advertisement system estimates a corresponding value of advertisement reach for the target audience, for example, by estimating a number of users of the target audience for each of whom the given bid value is expected to have resulted in at least one successful impression. The advertiser is provided a visual representation of a bid-reach landscape representing the estimated plurality of advertisement reach values as a function of the plurality of bid values. The advertising system provides, to the advertiser, one or more recommendations for bid values for which corresponding return-on-investment metrics exceed a specified threshold.