Free tool
Reach and Frequency Calculator
Two campaigns on the same impression count can reach ten times fewer people than each other. Reach and frequency are what separate them.
Frequency is the average number of times a reached person saw the ad. You get it by dividing impressions by reach, that is the number of unique people reached. Reach against the target audience gives the reach rate, expressed as a percentage.
Your frequency, for one person reached
How both are calculated
Frequency = Impressions ÷ Reach Reach rate = Reach ÷ Target audience × 100 Impressions needed = Reach × Target frequency
850,000 impressions across 210,000 people give a frequency of 4.05: every person reached saw the ad four times on average. Against a target audience of 1,200,000, reach is 17.5 %.
The same budget can produce two opposite outcomes. Concentrated on a narrow audience, it pushes frequency up and leaves reach low: the same people see the ad ten times. Spread across a broad audience, it reaches many people once. Neither extreme works, and impression count alone cannot tell them apart.
⚠️ Average frequency hides its distribution. An average of 4 can cover a majority reached once and a minority saturated at fifteen exposures. That minority is what produces ad fatigue, and it is invisible in the average.
What these two numbers decide
- The frequency cap on an awareness campaign, which gets set from this calculation rather than by feel.
- When to refresh creative. Frequency rising while CTR falls is the definition of creative fatigue, and it shows in these two curves before it shows in cost.
- Targeting size. Reach plateauing at a few percent of the target audience while frequency climbs means the targeting is too narrow for the budget committed.
Frequently asked questions
How do you calculate frequency?
Divide impressions by reach. For 850,000 impressions and 210,000 people reached: 850,000 ÷ 210,000 = 4.05 exposures per person on average.
What is the difference between reach and impressions?
Impressions count displays, reach counts people. One person seeing the ad five times counts as five impressions and one reach. That is why impressions alone say nothing about actual coverage.
What frequency should you target?
It depends on the objective: an awareness campaign for something new needs more frequency than a reminder campaign for a known brand. The useful reference is your own curve, the point where frequency climbs while CTR falls.
Frequency rising while results fall?
That is the classic sign of an audience too narrow for the budget, or a creative at the end of its life. Both are fixable, and not in the same way.
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Théo MaupiléFreelance Paid Media
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