Reach is the total number of unique individuals who are exposed to a specific piece of content within a given time period. It is one of the foundational metrics in influencer marketing - the answer to the most basic campaign question: "How many people actually saw this?"
What is Reach?
Reach counts unique people, not total exposures. If the same person sees a post three times (in their feed, via a share, and through the Explore page), they count as one in the reach figure but three in impressions. This distinction is critical:
- Reach = number of unique people who saw the content
- Impressions = total number of times the content was displayed (including repeat views by the same person)
Reach is almost always the more meaningful metric for campaign evaluation because it represents the actual size of the audience exposed to the brand message.
Types of Reach in Influencer Marketing
Organic reach - people who saw the content through non-paid, algorithmic distribution (their feed, the Explore page, hashtags). This is the default reach an influencer generates from a post without any paid amplification.
Paid reach - people who saw the content because the brand or influencer paid to promote it (boosted posts, whitelisted content, Spark Ads). Paid reach allows precise audience targeting and scale beyond the creator's organic audience.
Earned reach - people who saw the content because someone else (another user or publication) shared it organically. Earned reach is not bought and not algorithmically served - it is generated purely by the content's ability to travel through social sharing.
Total campaign reach - the sum of unduplicated unique people reached across all posts, all creators, and all formats in a campaign. Calculating true unduplicated reach across multiple creators requires sophisticated analytics tools, as the same person may follow several participating influencers.
Potential Reach vs. Actual Reach
When influencer platforms report a creator's "reach," they often mean potential reach - the creator's total follower count across platforms, as if every follower saw every post. Actual reach is always lower due to algorithmic filtering, inactive followers, and posting-time effects.
A creator with 200,000 Instagram followers might achieve actual reach of 30,000–60,000 per post (15–30% follower reach rate). This gap between potential and actual reach should be factored into campaign forecasting.
Setting Reach KPIs for Influencer Campaigns
When defining campaign objectives:
1. Awareness campaigns → reach is the primary KPI. Optimise for the highest unique reach at acceptable cost-per-reach.
2. Engagement campaigns → reach is secondary to engagement rate. A smaller but more engaged audience is preferable.
3. Conversion campaigns → reach matters less than audience quality (demographic alignment, purchase intent, past behaviour).
Reach KPIs should be based on realistic actual reach estimates, not potential reach. Request post-campaign analytics showing actual reach from the influencer's native platform.
Cost Per Reach (CPR)
> CPR = Total campaign cost ÷ Total unique reach
CPR allows cross-campaign and cross-channel comparison - how much did each unique person reached cost? It can be compared across influencer tiers, content formats, and paid media channels to optimise budget allocation.
