How to calculate impressions from GRPs

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Lately some of Blue Light Media’s clients have asked that we measure the GRP of various paid media campaigns on Google AdWords, Facebook and Instagram and even influencer initiatives.

Table of Contents Show

Calculating GRP Does Not Measure the Impact of a Digital Campaign
A Few Thoughts on Media Planning
Thanks for reading! If you enjoyed the article I’d appreciate a few claps. If you have any questions about your marketing efforts, or just want to say hello, feel free to email me at .

GRP stands for Gross Rating Point. A standard measure in advertising, it measures advertising impact. You calculate it as a percent of the target market reached multiplied by the exposure frequency. Thus, if you get advertise to 30% of the target market and give them 4 exposures, you would have 120 GRP. (via Marketing Profs)

This measurement has traditionally been used by media planners and buyers to determine how many people within a certain target audience might have seen their ads. (via Digiday)

So the question is, how might one calculate GRP for digital campaigns? I searched high and low (i.e. went to the 3rd page of Google), and couldn’t find a clear answer so I developed the following formula to measure GRP:

(reach) / (target market) x 100 = Y% (percentage of market reached)(impressions) / (reach) = Z (ad frequency)

Y x Z = GRP

So if a campaign receives 1,200,000 impressions and reaches 589,000 people in a target market of 5,000,000 it would look like this:

(589,000) / (5,000,000) x 100 = 11.8% of target audience reached
(1,200,000) / (589,000) = 2.03
11.8 x 2.03 = 24GRP

I apologize for how rudimentary the above formula is, algebra was never my strong suit.

Please keep in mind that measuring GRP is not something I’ve found to be widely used in the digital marketing world. With that said, I’ve asked a few experts in the space and they seem to agree with the above formula.

Calculating GRP Does Not Measure the Impact of a Digital Campaign

As you may have assumed by now, calculating the GRP of digital campaigns does not measure it’s effectiveness. Facebook, Google, Snapchat among other self serve ad platforms offer metrics that are more meaningful to companies and should be reported and analyzed more closely.

The metrics that our clients find most valuable are:

CPM or cost per 1,000 views
Click Through Rate (CTR)
Cost Per Click (CPC)
Cost per Conversion — or the cost to achieve a desired outcome past clicks.

Other forms of metrics we use to measure the effectiveness of campaigns are:

Engagement rate
Engagement quality — this is tricky to measure, but we legitimately read through comments and see how many people are actually trying to communicate with a brand and what might be spam comments.
Amount of clicks through tracked links such as Bitly
Sales through affiliate links.

For me, the bottom line is always sales. Ask yourself, “has my sales or revenue increased since I implemented X marketing initiatives?”.

A Few Thoughts on Media Planning

In my opinion, no one ad or campaign is going to make or break a company (usually). A healthy mix of distributing quality content via organic and paid media is crucial. Don’t forget about SEO, e-mail and traditional marketing efforts (we’ve found some print, outdoor and direct mail to still be effective in some markets).

Remember that it is crucial to first determine what your measurement of success for a specific campaign is before launching it. Ask yourself what your goal is when planning our campaigns. Is the goal more email subscriptions, growing your audience on Instagram or content downloads? All of these (and more) attribute to a robust and effective marketing funnel and will play a big part in the success of your campaigns before you actually make a sale.

Thanks for reading! If you enjoyed the article I’d appreciate a few claps. If you have any questions about your marketing efforts, or just want to say hello, feel free to email me at .

In advertising, a gross rating point (GRP) measures impact.[1] GRPs help answer how often "must someone see it before they can readily recall it" and "how many times" does it take before the desired outcome occurs.[2]

Gross rating points are a measure of the impact by a campaign using a specific medium or schedule. It quantifies impressions as a percentage of the target population, multiplied by frequency. This percentage may be greater, or in fact much greater, than 100.

Target rating points express the same concept, but with regard to a more narrowly defined target audience.[3][4]

GRPs are used predominantly as a measure of media with high potential exposures or impressions. Nielsen Media Research is an example of a company which uses GRPs.[5]

With "today's fragmented media world" the value of GRP is, according to the Advertising Research Foundation's Journal of Advertising Research, even greater than in the pre-Internet era.[6] Since "the required frequency changes with the product and the competitive climate it is in",[2] the purpose of the GRP metric is to measure impressions compared to the number of people in the target for an advertising campaign.[3] GRP values are commonly used by media buyers to compare the advertising strength of components of a media plan.

For conventional media such as radio and TV, multi-tasking has reduced the value per GRP, and a measure named Persuasion Rating Point (PRP) was proposed in mid 2020.[7]

"One GRP is one percent of all potential adult television viewers (or in radio, listeners) in a market." If they are exposed to the ad three times, then that is 3 GRPs.[2]

GRPs are simply total impressions related to the size of the target population: They are most directly calculated by summing the ratings of individual ads in a campaign.

Mathematically:

GRPs (%) = 100 * Impressions (#) ÷ Defined population (#)[3] GRPs (%) = 100 * Reach (%) × Average frequency (#)

Two examples:

If an average of 12% of the people view each episode of a television program, and an ad is placed on 5 episodes, then the campaign has 12 × 5 = 60 GRPs.
If 50% view three episodes, that's 150 GRPs.

^ Nick Corasaniti (December 3, 2019). "Ad of the Week: When the placement is as important as the ad". The New York Times. an advertising metric that measures impact
^ a b c Philip H. Dougherty (June 22, 1976). "Advertising". The New York Times.
^ a b c Farris, Paul W.; Neil T. Bendle; Phillip E. Pfeifer; David J. Reibstein (2010). Marketing Metrics: The Definitive Guide to Measuring Marketing Performance. Upper Saddle River, New Jersey: Pearson Education, Inc. ISBN 0-13-705829-2. The Marketing Accountability Standards Board (MASB) endorses the definitions, purposes, and constructs of classes of measures that appear in Marketing Metrics as part of its ongoing Common Language in Marketing Project.
^ American Marketing Association Dictionary. "Dictionary". Archived from the original on 2012-11-21. Retrieved 2012-11-29.. Retrieved 2013-2-11. The Marketing Accountability Standards Board (MASB) endorses this definition as part of its ongoing Common Language in Marketing Project.
^ Will CCPA Force Advertisers to Take Media Measurement Into Their Own Hands? Published by Broadcasting + Cable on January 7, 2020, consulted on January 9, 2020
^ P. Neijens; H. Voorveld (2015). "Cross-Platform Advertising: Current Practices and Issues for the Future: Why the Gross Rating Point Metric Should Thrive in Today's Fragmented Media World" (PDF). Journal of Advertising Research. doi:10.2501/JAR-2015-016. S2CID 167344548.
^ F. Findley; K. Johnson; D. Crang (2020-05-26). "Effectiveness and Efficiency of TV's Brand-Building Power: A Historical Review: Why the Persuasion Rating Point (PRP) Is a More Accurate Metric than the GRP". Journal of Advertising Research. doi:10.2501/JAR-2020-011. S2CID 219770387.