About the GRP & Reach Frequency Calculator
This GRP calculator links the three numbers every broadcast and out-of-home media plan is built on: reach (the percentage of the target audience exposed at least once), average frequency (how many times those people are exposed) and gross rating points, which are simply reach × frequency. Pick the number you want to solve for and enter the other two.
It is built for media planners, buyers, brand managers and marketing students working with TV, radio, streaming, podcast or billboard campaigns. Add the size of the target audience and the campaign budget to translate rating points into total impressions, the number of people reached, the cost per rating point (CPP) and the cost per thousand impressions (CPM).
When the ratings are measured against a specific target audience (for example adults 25–54) rather than the whole population, the same maths gives target rating points, or TRPs. GRPs count duplicated exposures, so 200 GRPs can mean 100% reach at a frequency of 2 or 40% reach at a frequency of 5 — always look at reach and frequency together.
How to use the grp & reach frequency calculator
- 1Choose whether to solve for GRPs, frequency or reach.
- 2Enter the two known values from your media plan or post-buy report.
- 3Add the target audience size to convert points into impressions and people reached.
- 4Enter the budget to see cost per point and CPM.
- 5Use the chart to see how the same GRPs trade reach against frequency.
Formula and method
One rating point is 1% of the target audience. Gross rating points add up every exposure, so a campaign that reaches 60% of the audience an average of 4 times delivers 240 GRPs. Rearranging gives frequency = GRP ÷ reach and reach = GRP ÷ frequency; reach can never exceed 100%, so a plan always needs a frequency of at least GRP ÷ 100.
Because each GRP is 1% of the audience, total impressions are GRP ÷ 100 × audience size. Cost per point divides the budget by the GRPs bought and is the standard unit for pricing TV and radio, while CPM divides the budget by impressions in thousands so you can compare with digital media. TRPs use exactly the same formulas, measured against a narrower target audience.
- Reach
- % of the target audience exposed at least once
- Frequency
- Average number of exposures among those reached
- GRP
- Gross rating points (duplicated % of audience)
- CPP
- Cost per rating point
Worked examples
60% reach at a frequency of 4
Reach 60% × frequency 4 = 240 GRPs. With a 2 million-person audience that is 2.4 × 2,000,000 = 4.8 million impressions reaching 1.2 million people. A $120,000 budget works out to $500 per point and a $25 CPM.
Frequency from a 300-GRP TV flight
A flight of 300 GRPs that reaches 75% of the audience shows the ad 300 ÷ 75 = 4 times on average. On a 500,000-person market that is 1.5 million impressions; $45,000 buys points at $150 each, a $30 CPM.
Reach from a radio schedule
Dividing 180 GRPs by an average frequency of 3.6 gives a reach of 50%, or 600,000 of the 1.2 million listeners in the target. Total impressions are 1.8 × 1,200,000 = 2.16 million.
Frequently asked questions
How do you calculate GRP?+
Multiply reach (as a percentage of the target audience) by average frequency. A campaign reaching 50% of the audience an average of 3 times delivers 50 × 3 = 150 gross rating points.
What is the difference between GRP and TRP?+
GRPs are usually quoted against a broad base such as all households or all adults, while target rating points (TRPs) are measured against the specific audience you want, such as women 18–34. The formula is the same; only the audience base changes.
Can GRPs be more than 100?+
Yes. GRPs count duplicated exposures, so they routinely exceed 100. Reach cannot exceed 100%, but 400 GRPs simply means the audience was exposed the equivalent of four times over.
What is cost per point (CPP)?+
CPP is the cost of buying one rating point — 1% of the target audience — and is calculated as the budget divided by the GRPs delivered. Broadcasters and buyers use it to compare dayparts, stations and markets.
How do I convert GRPs into impressions?+
Divide GRPs by 100 and multiply by the size of the target audience. For example, 250 GRPs against an audience of 1 million people equals 2.5 million impressions.