How do I calculate the reach of my influencer marketing campaign?

Do not add follower counts, that massively overstates reach, since only a fraction of followers see a post and it double-counts people who follow several creators.

Sum the actual reach or impressions of each post from platform analytics instead and label clearly whether you mean reach (unique people) or impressions (total views).

Account for audience overlap between creators, since the same people seeing multiple posts inflates a summed figure. True unique reach adjusts for it.

The single most important thing is what not to do: do not add up follower counts. Summing followers is the most common reach mistake and it massively overstates your real reach, because followers are not views (only a fraction of a creator followers see any given post) and because adding followers across creators double-counts everyone who follows more than one of them. A campaign with creators totalling two million followers does not reach two million people, not even close. So the headline number your boss probably wants, total followers, is exactly the wrong one and using it makes the campaign look far bigger than it was.

The right way is to sum actual reach or impressions from each post performance, taken from platform analytics. For each creator post, get the real numbers (impressions, reach, views) from the platform insights (creators can share these or you get them on your own posts), then add the actual reach figures across the campaign rather than the potential follower numbers. Two distinctions matter for getting it right. First, reach versus impressions: reach is the number of unique people who saw the content, impressions is the total number of times it was seen (one person seeing it three times is one reach, three impressions), so decide which question you are answering, unique audience size (reach) or total exposure (impressions) and label it clearly. Second, audience overlap: if several creators share overlapping audiences, the same people saw multiple posts, so summing reach across them still double-counts to a degree and a true unique-reach figure adjusts for that overlap (some platforms and tools estimate this). For most reporting, summing the real per-post reach gives a defensible campaign reach as long as you call it reach (not followers) and note that overlap means the unique figure may be somewhat lower. So calculate reach from actual post analytics, sum real reach not follower potential, distinguish reach from impressions and account for audience overlap rather than double-counting, which gives your boss a number that is honest and holds up rather than an inflated follower total that falls apart under scrutiny.

Where Flinque connects to reach is before the campaign and on the overlap problem: it shows a creator genuine reach-relevant audience (real, engaged followers rather than inflated counts) and helps you spot creators with overlapping audiences, so your projected and actual reach are based on real numbers and you avoid double-counting the same people across creators. The post-campaign reach calculation itself comes from platform analytics but starting from real audience data is what keeps the number honest.