How this calculator works
Reach is the share of the target audience exposed to an ad at least once. Frequency is the average number of exposures per reached person. Gross rating points multiply reach, expressed as a percentage, by frequency. A 25% reach at an average frequency of three is 75 GRP. GRPs count total exposure, so the same GRP can come from wide reach at low frequency or narrow reach repeated often. Unlike reach, GRP can exceed 100 because one person can be counted several times.
Formula
Reach percentage = people reached / total target audience × 100. GRP = reach percentage × average frequency. Total impressions = people reached × average frequency.
Worked example
250,000 people reached out of a 1,000,000 target audience is 25% reach. At an average frequency of three the campaign delivers 75 GRP and 750,000 impressions.
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Frequently asked questions
What is the difference between GRP and TRP?
Gross rating points use the total population or the total audience for the medium. Target rating points use only the campaign's target audience as the base. If the target audience and the measured audience differ, the two numbers will differ.
Can GRP exceed 100?
Yes. GRP is reach percentage times frequency, and frequency can be greater than one, so 100 GRP is common and campaigns often run far higher. Only reach itself is capped at 100% of the audience.
Is a higher GRP always better?
No. GRP measures weight of exposure, not impact. The same GRP can be spent on broad reach or repeated exposure, and the right mix depends on whether the goal is awareness, recall or action. Diminishing returns apply as frequency rises.