How to Calculate Influencer Reach

Figuring out an influencer's true reach can feel like a guessing game, but it doesn't have to be. Going beyond a simple follower count is the first step toward launching influencer campaigns that actually deliver results. This guide will walk you through exactly how to calculate and analyze influencer reach, so you can partner with creators who genuinely connect with your target audience.

First, Let's Get Clear: What is Influencer Reach (and What It Isn't)?

Before you can calculate anything, it’s important to understand what you're actually measuring. In the world of social media, "reach" and "impressions" are often used interchangeably, but they mean very different things.

• Reach is the total number of unique people who see a piece of content. If 10,000 unique accounts saw an influencer’s Reel, its reach is 10,000.
• Impressions are the total number of times a piece of content was displayed, regardless of whether it was clicked. If those same 10,000 people saw the Reel an average of two times each, the content would have 20,000 impressions.

Impressions will almost always be higher than reach. While impressions can indicate high visibility or viral potential (content appearing multiple times in feeds), reach is the metric you need to focus on to understand the actual size of an influencer’s audience for a given post.

Why Follower Count Is The Ultimate Vanity Metric

The most common mistake brands make is equating an influencer's follower count with their reach. A creator could have 500,000 followers, but if only 5% of them ever see a post, the effective reach is just 25,000 people. Basing your partnership decisions on follower count alone is like buying a car based solely on its paint job - it tells you nothing about the performance.

Here’s why it's so misleading:

• Inactive and Fake Followers: Over time, any account accumulates inactive followers or even bots. Some "influencers" even purchase fake followers to inflate their numbers. These accounts will never see the content, rendering them completely useless to a brand partner.
• Algorithmic Feeds: Every major platform - Instagram, TikTok, YouTube, X - uses an algorithm to decide what content to show users. They don't show every post to every follower. Platform algorithms prioritize content based on engagement, relevance, and a hundred other factors, meaning only a fraction of an influencer's followers will ever see their content organically.
• Audience Apathy: Some followers may have simply lost interest. They might have followed a creator for a specific trend years ago and now scroll right past their content without a second thought.

Follower count is a starting point - a measure of potential reach. But to understand actual reach, you need to look at post-level performance data.

How to Actually Calculate an Influencer's Reach

To get a true sense of an influencer’s reach, you have to move beyond their public profile and into their actual performance metrics. This requires a bit of math and, ideally, direct collaboration with the influencer to get accurate data. Here are the key calculations you should use. Learn how to analyze influencer metrics to make more informed decisions.

1. Average Reach Per Post

Individual post performance will always vary. One Reel might take off and reach 1 million people, while the next one only reaches 30,000. To get a realistic expectation, you should calculate their average reach across a set of recent, representative posts (e.g., their last 5-10 feed posts or Reels).

The formula is simple:

(Total Reach from a collection of posts) / (Number of posts) = Average Reach Per Post

Example:

Let's say you're looking at an influencer’s last 5 Instagram feed posts. They provide you with screenshots from their analytics showing the reach for each one:

• Post 1: 25,000 Reach
• Post 2: 35,000 Reach
• Post 3: 28,000 Reach
• Post 4: 42,000 Reach
• Post 5: 30,000 Reach

Calculation:

(25,000 + 35,000 + 28,000 + 42,000 + 30,000) / 5 = 160,000 / 5 = 32,000

This influencer has an Average Reach Per Post of 32,000. This is a much more practical and realistic number to work with than their total follower count.

2. Reach Rate

Average reach is useful, but it doesn't help you compare influencers of different sizes. An influencer with 1 million followers and an average reach of 50,000 is performing very differently than an influencer with 100,000 followers and an average reach of 30,000. This is where Reach Rate comes in.

Reach Rate frames the average reach as a percentage of the influencer's total follower count. This metric helps standardize performance and shows you how effectively a creator connects with their existing audience. You can also calculate their engagement rate on Instagram to get a more complete picture.

The formula is:

(Average Reach Per Post / Total Followers) x 100% = Reach Rate

Using our previous example of the influencer with an average reach of 32,000, let's assume they have 150,000 followers.

Calculation:

(32,000 / 150,000) x 100% = 21.3%

Their Reach Rate is 21.3%. Now you have a powerful metric for comparison.

What’s a Good Reach Rate?

Benchmarks vary widely by platform, content type, and follower count, but here are some general guidelines for Instagram, a common starting point for many brands:

• Below 10%: Potentially low or indicates the influencer relies on one or two viral Reels. Scrutinize a bit more.
• 10-30%: A solid and healthy range for most accounts.
• 30-60%: Very strong engagement and algorithmic favor. This creator consistently reaches a large portion of their audience.
• Above 60%: Excellent performance, often characteristic of creators with highly engaged, niche communities or those with recent viral growth.

Mega-influencers (1M+ followers) naturally have lower reach rates, while micro-influencers (10k-100k followers) can have exceptionally high rates because of their focused, tight-knit communities.

3. Consider Platform-Specific Metrics

Reach doesn't look the same on every platform. When evaluating an influencer, you need to consider the specific format and platform you want to use for your campaign.

• Instagram: Look at reach data separately for Feed Posts, Reels, and Stories. Story reach is often measured by total unique views on the first frame, and it tends to be lower than post reach. Reel views can be very high due to an effective discovery algorithm, but check if those high views translate into authentic engagement and saves.
• TikTok: TikTok's algorithm is entirely discovery-based. It's common for a creator with only 10,000 followers to have a video reach millions of people on the "For You" page. For TikTok, focus less on follower count and more on the creator's average video views over their last 10-15 videos. Consistency is what you want to see. To get a deeper understanding, analyze TikTok account performance thoroughly.
• YouTube: The primary metric here is video views. Calculate the influencer’s average views per video on their last 5-10 uploads (excluding Shorts, which perform differently). Subscribers are a good indicator of a loyal fanbase, but average views tell you the reality of their current viewership.

How to Get This Data (Without Being Awkward)

These calculations rely on data that isn't publicly visible. You'll need the influencer to provide it. Don't worry - this is a standard part of the process for professional creators and brands.

Simply ask for screenshots of their post-level analytics from the past few weeks. Frame it as part of your standard campaign planning.

Here’s what a polite request might look like:

"Hi [Influencer Name], we're really excited about the possibility of collaborating! As we build out our campaign projections, could you please share a few recent screenshots of your analytics? We’d love to see the reach and engagement on a few of your recent feed posts/Reels, as well as an overview of your audience demographics. This will help us make sure we're setting up the campaign for success. Thanks!”

When you get the screenshots, look for:

• Post Reach (not Impressions): Make sure the screenshot clearly shows the "Accounts Reached" metric.
• Audience Demographics: Pay attention to the top locations (cities/countries), age range, and gender breakdown. Is there a strong overlap with your target customer?
• Consistency: Are the numbers pretty consistent from post to post, or is their average skewed by one viral hit from six months ago?

Beyond the Numbers: The Quality of the Reach

Calculating reach is a numbers game, but choosing the right influencer isn't. Once you have the data, you need to add a layer of qualitative analysis to find the perfect fit.

Ask yourself:

• Is it the *Right* Reach? An influencer might have a reach of 100,000, but if their audience is primarily 18-year-old men in Brazil and you're selling sustainable skincare to 30-year-old women in the UK, that reach is worthless to you. Always analyze audience demographics. A smaller, perfectly aligned reach is always better than a massive, misaligned one.
• Does Their Audience Trust Them? Look at the comments. Are people asking for advice on a product the influencer recommended? Are the replies positive and conversational? High-quality engagement - thoughtful comments, shares, and saves - is a strong indicator of an audience that listens and trusts the creator's recommendations.
• Does their Content Align with Your Brand? Does the influencer's visual style, tone of voice, and overall brand feel compatible with yours? An authentic partnership relies on natural alignment. If the collaboration feels forced, their audience will know, and the campaign's impact will suffer no matter how wide the reach is.

Final Thoughts

Evaluating an influencer’s reach is about shifting your focus from followers to actual performance. By using metrics like average reach per post and reach rate, you can make data-informed decisions, set realistic campaign goals, and partner with creators who can deliver tangible results for your brand.

We know that once a campaign goes live, tracking performance and understanding a campaign's organic impact is just as important. That's why we built the analytics dashboard in Postbase to be clean and straightforward. You get a clear view of what’s working across all your social platforms in one place, helping you see the real-world results of your content and collaborations without wrestling with confusing spreadsheets or complicated reports.