GRP計算器：收視點與曝光

Gross rating points (GRP) summarize the weight of an advertising campaign by combining reach and average frequency. Reach is the percentage of the target audience exposed at least once, while frequency is the average number of exposures among reached people. Multiplying the two creates a single delivery measure. A campaign reaching 45.5% of its audience an average of 3.2 times delivers 145.6 GRPs. GRP can exceed 100 because it counts repeated exposures, not unique people. One hundred GRPs might mean 100% reach at a frequency of one, 50% reach at a frequency of two, or 20% reach at a frequency of five. Those plans have the same GRP but very different communication effects. Brand launches may prioritize broad reach, while reminder or direct-response campaigns may require higher repetition among a narrower audience. When target population is supplied, people reached equals population multiplied by reach as a decimal. Gross impressions equal people reached multiplied by average frequency. In a one-million-person market, 45.5% reach represents 455,000 people; at 3.2 exposures each, that is about 1,456,000 gross impressions. Because reported reach and frequency are often modeled or survey-derived, the impression result should be treated with matching precision. Media planners use GRP to compare schedules, allocate weight across markets, monitor delivery against a plan, and calculate cost per rating point. GRP alone does not measure creative quality, attention, viewability, conversion, incremental sales, or audience duplication across platforms. Digital impression counts and television ratings may use different measurement universes, so definitions must be aligned before adding them together. Use the same target demographic, geography, date range, and measurement source for every scenario. Separate planned GRPs from delivered GRPs and check whether frequency is evenly distributed; an average can hide people who saw an ad many times and others only once. Pair GRP with cost, incremental reach, frequency distribution, brand lift, and conversion metrics. The GRP formulas perform the delivery arithmetic, but campaign effectiveness still depends on audience quality, creative relevance, placement, and business outcomes.