Reference library · TV budgeting
GRP (Gross Rating Point)
GRP (Gross Rating Point) is the sum of the ratings of every spot in a schedule, expressed as percentage points of a defined audience base. One GRP equals 1% of that base reached once; the total is cumulative and includes people counted more than once if they see multiple spots.
Formula
Worked example
A campaign for a snack brand runs 120 TV spots over a 4-week flight against adults 18-49 in a market with a universe of 3,200,000. Measurement shows an average rating of 2.5% per spot. GRP = 120 x 2.5 = 300. That 300 GRP corresponds to roughly 65% reach at an average frequency of 4.6, which the planner checks against the flight's 280-320 GRP weight target before releasing the next week's buy.
How it is used
Planners add up ratings spot by spot, then week by week, to track delivered weight against the planned total and to compare weight across markets or competitors on a common scale. It also feeds reach/frequency curve models that convert cumulative GRPs into estimated unique reach.
The common mistake
Reading GRP as unique reach: 300 GRP does not mean 300% of the audience saw the ad, it's cumulative rating that includes people exposed more than once.