Gross rating points measure the total exposure a campaign buys: 100 GRPs could mean reaching 50% of the audience twice or 25% four times. Media planners use GRPs to compare TV, radio and outdoor schedules.
How to use the GRP Calculator – Gross Rating Points
- Total target audience
- Audience reached
- Average frequency per viewer
- Campaign cost
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter the size of the target audience, the number of people reached, the average frequency and the campaign cost.
Tips
- Use figures for the same period (a month, a quarter or a year) for every input so ratios compare like with like.
- Track the metric over time – the trend usually tells you more than a single value.
- Compare your result with industry benchmarks, which vary a lot between sectors.
- Treat the result as a starting point for a decision, then check the assumptions behind each input.
Common mistakes to avoid
- Mixing monthly and yearly numbers in the same calculation.
- Using revenue where the formula needs profit (or the other way round).
- Forgetting hidden costs such as taxes, fees, overheads or your own time.
Inputs explained
| Field | What to enter |
|---|---|
| Total target audience | A number |
| Audience reached | A number |
| Average frequency per viewer | A number |
| Campaign cost | Amount in your currency |
What each result means
- Reach percentage = [Audience reached]÷[Total target audience]×100
- Gross rating points (GRP) = [Reach percentage]×[Average frequency per viewer]
- Total impressions = [Audience reached]×[Average frequency per viewer]
- Cost per rating point = [Campaign cost]÷[Gross rating points (GRP)]
- Cost per thousand impressions = [Campaign cost]÷[Total impressions]×1000
Example values
How the main result changes when Total target audience changes and everything else stays at the example values above:
| Total target audience | Gross rating points (GRP) |
|---|---|
| 1,000,000 | 288 |
| 1,500,000 | 192 |
| 2,000,000 | 144 |
| 2,500,000 | 115.2 |
| 3,000,000 | 96 |
| 4,000,000 | 72 |
Formula
Reach % = people reached ÷ target audience × 100GRP = reach % × average frequencyCost per point = campaign cost ÷ GRPWorked example
Inputs — Total target audience: 2,000,000; Audience reached: 900,000; Average frequency per viewer: 3.2; Campaign cost: $150,000.
Results — Reach percentage = 45 %; Gross rating points (GRP) = 144; Total impressions = 2,880,000; Cost per rating point = $1,041.67; Cost per thousand impressions = $52.08.
Frequently asked questions
What is a GRP?
One rating point equals 1% of the target audience; GRPs add up all exposures.
What is the difference between GRP and TRP?
TRPs measure only the specific target group; GRPs may use a broader population.
How many GRPs does a campaign need?
Many brand campaigns aim for 100–300 GRPs per flight.
What formula does the GRP Calculator – Gross Rating Points use?
Reach % = people reached ÷ target audience × 100.