Frequency (Ad Frequency)
MetricFrequency is the average number of times each reached person saw your ad over a given period — impressions divided by unique people reached.
Reach is how many different people saw your billboard. Frequency is how many times each of them drove past it. If 10,000 people saw your ad and it was shown 40,000 times, each person saw it about 4 times on average.
Frequency = Impressions ÷ Reach
A campaign serves 250,000 impressions to 50,000 unique people in a week. Frequency = 250,000 ÷ 50,000 = 5.0 — each person saw the ad five times that week.
Frequency rising while reach stays flat is the signature of audience saturation: extra budget is buying repeat impressions to the same people rather than new people. Because it is an average, it also hides the tail — a frequency of 4 often means most people saw the ad twice and a small group saw it fifteen times.
Last reviewed August 28, 2026.