Reach: the number, and what it hides
The number of distinct people who saw the ad at least once.
Why reach matters
Reach and impressions diverging is the story of an account saturating: the same people, more often, for more money.
What this looks like with real numbers
Spend $10,000 and reach 400,000 people in month one. Spend the same in month two and reach 180,000. The audience has not grown, so you are buying the same people more often, and that divergence is the saturation signal.
What it does not tell you
Reach is per platform and per window. It cannot be added across platforms without double-counting people who are on both.
The mistake people actually make
Adding reach across Meta and TikTok to claim a total. The overlap between them is substantial and the combined figure is fiction.
Questions, answered.
How do you calculate reach?
Distinct people served at least one impression. The number of distinct people who saw the ad at least once.
What goes wrong with reach?
Adding reach across Meta and TikTok to claim a total. The overlap between them is substantial and the combined figure is fiction.
What does reach not tell me?
Reach is per platform and per window. It cannot be added across platforms without double-counting people who are on both.
Change the creative, not the dashboard
The number of distinct people who saw the ad at least once.