GRP Calculator (Gross Rating Point)
Calculate GRP (Gross Rating Point) from reach and frequency, from impressions and target population, or total GRP across a full campaign's ad spots. Instant results with formula breakdown.
GRP = Reach (%) × FrequencyAdjust Variables
Interactive Step-by-Step Calculation Proofs
View how variables resolve algebraically down to peer-reviewed standard outputs.
Why Use This Calculator
GRP (Gross Rating Point) is the standard unit media planners use to measure the total weight of an advertising campaign — how much exposure it delivers to a target audience, combining both how many people were reached and how often. The most common formula is GRP = Reach × Frequency, where Reach is the percentage of the target audience exposed at least once, and Frequency is the average number of times each person was exposed. GRP can also be calculated directly from impressions: GRP = (Impressions ÷ Target Population) × 100 — useful when reach and frequency aren't tracked separately but total delivered impressions are known. Because GRP counts total exposures rather than unique people, it can (and often does) exceed 100% for campaigns with high frequency. For a full campaign spanning multiple ad spots or placements, Total GRP is simply the sum of each spot's individual rating: Total GRP = Average Rating per Spot × Number of Spots. GRP is a legacy metric from TV and radio media buying but is still widely used in modern cross-channel campaign planning to compare weight of exposure across networks. Pair it with the CPM calculator to connect campaign weight (GRP) to campaign cost efficiency (cost per 1,000 impressions).
Mathematical Formula Explanation
Calculated standard benchmarks are based on direct functional dependencies. The primary calculation logic follows this formula:
GRP = Reach (%) × FrequencyThe three modes above compute GRP from whichever inputs are actually tracked for a given campaign. Reach × Frequency is the classic formula when both are measured directly (typical of TV/radio panel data). Impressions ÷ Population is the digital-era shortcut when only raw delivered impressions and audience size are known — it implicitly derives an average frequency as a side effect. Total GRP for a multi-spot campaign is just the sum of each spot's individual rating, which simplifies to average rating × spot count when ratings are similar across spots.
Worked Examples (Step-by-Step)
These examples show GRP calculated from reach and frequency, from impressions and population, and totaled across a multi-spot campaign.
Example 1: GRP From Reach and Frequency
“A campaign reaches 60% of its target audience with an average frequency of 3 exposures per person. What is the GRP?”
- REACH: 60
- FREQUENCY: 3
- GRPRF: 180
Example 2: GRP From Impressions and Population
“A campaign delivers 2,400,000 impressions against a target population of 2,000,000 people. What is the GRP, and what average frequency does that imply?”
- IMPRESSIONS_GRP: 2,400,000
- TARGETPOPULATION: 2,000,000
- GRPIP: 120
- IMPLIEDFREQUENCY: 1.2
Example 3: Total Campaign GRP
“A radio campaign runs 40 spots, each averaging a 5% rating among the target audience. What is the total GRP for the campaign?”
- AVGRATINGPERSPOT: 5
- NUMBEROFSPOTS: 40
- TOTALGRP: 200
Common Mistakes & Edge Cases
- Treating GRP as a count of unique people reachedGRP measures total exposures (reach × frequency), not unique audience size. A campaign with 200 GRP could mean 100% of the audience saw it twice, or 50% saw it four times — GRP alone can't tell those apart. Pull reach and frequency separately if the question is really "how many different people did this reach."
- Comparing GRP across campaigns measured against different population basesA campaign rated against a national population and one rated against a single DMA (media market) aren't comparable on GRP alone, even at the same numeric value — the national number represents vastly more total exposures. Confirm both campaigns used the same population denominator before comparing.
- Using GRP instead of TRP for a narrow target demoGRP is rated against the total population; TRP (Target Rating Point) is rated only against the specific demo a campaign is trying to reach. A campaign targeting women 25–34 will show a lower, more accurate TRP than GRP — using GRP here overstates how efficiently the campaign reached its actual intended audience.