A math equation that multiplies the number of times an ad is run by the percentage of the target audience that sees it, multiplied by 100. Gross rating points (GRPs) are commonly used in television ad buying to help media planners decide when and where to place their ads. Though the math is a bit too complicated for this short description, GRPs can be calculated for online ads as well. Some planners find this helpful when determining their media mix of TV and online advertising.