How The Instagram Algorithm Works in 2021


The main goal of Instagram’s algorithm is to keep users on the app longer. More screen time means more content consumption which leads to more opportunity for ad revenue, and now, eCommerce.

The platform’s algorithm learns users’ behavior over time, serving up increasingly relevant content based on the types of posts a consumer interacts with most. But a factor that’s often overlooked is that there are actually five separate algorithms, one for each of Instagram’s platform features:

  1. Stories
  2. Reels
  3. Feed Posts
  4. Shopping
  5. IGTV

That’s right; each feature within Instagram’s app has different factors that affect how a user’s content is ranked and weighted. The features themselves are also ranked and weighed against each other.

Instagram’s Basic Algorithm Formula

Before we explain what specific behaviours will be affecting each of Instagram’s 5 feature algorithms in 2021, it’s important to first understand the foundation of how the algorithm works in the first place.

Let’s start with the overall factors that Instagram says determine whether or not a piece of content will be served to viewers. In order of most heavily weighted to least, they are:

  1. Interest; has the user expressed previous interest in this type of content?
  2. Relationship; The algorithm prioritises accounts you care about; family, friends, and those accounts you search for or engage with on a regular basis.
  3. Timeliness; When was a piece of content published? Users that post more consistently will rank higher in the algorithm.
  4. Frequency; this refers to frequency of app use by the user. If a person frequently checks Instagram, their feed will look more chronological because the algorithm will constantly be trying to serve you new content. If you check less often, your feed will contain more “relevant” content to keep you engaged.
  5. Following; how active a profile’s following is will affect whether or not that profile’s content will be served to a wider audience. This is why it’s worthwhile to remove “ghost” or “bot” users that affect this part of the algorithm.

How the Algorithm is Changing in 2021

In addition to the 5 original factors above, there are 5 main platform features inside Instagram, each with their own unique algorithm.

Stories; With half a billion people using Stories every day (an estimated 88% of active Instagram users) Stories are Instagram’s main focus. Marketing Dive recently reported that influencer impact on IG Stories is up by almost 60% since the pandemic, a number that’s expected to hold steady, and even increase.

Overall, Video content is more heavily weighted than photos and feed posts, a trend that’s expected to continue as we move into 2021, with a huge focus on Stories over in-feed video. Stories are the in-platform feature that matter most to the overall algorithm right now.

Reels is Instagram’s newest “main” feature and therefore doesn’t have as much historical data to pull from when deciding what content to serve the viewer. However, even though the Reels algorithm is still maturing, Instagram is heavily invested in increasing user adoption to draw them away from TikTok.

Feed Posts; Behind Stories and Reels is Feed Posts. While not as many users post to the main feed as they do to Stories, many report consuming more content from this source via their own personal feed as well as the explore tab. More than 50% of Instagram users use the explore tab every month. Leveraging hashtags and keywords allows accounts to become more discoverable while also increasing their ranking in the algorithm.

Shopping is perhaps the feature that will bring the most change to Instagram’s algorithm in 2021. At Allegiant Media, we anticipate the relevance of a user’s shopping behaviour to increase significantly over the course of the year, especially in light of the app introducing the shopping tab to its home screen, quite literally signalling the feature’s new importance.

Across the board, every social media platform introduced new ways for brands, influencers and companies to sell to audiences in 2020. With so much purchasing activity being done online in light of the pandemic, every enterprise moved quickly to adjust to this massive shift in consumer behaviour.

There are now multiple ways to engage in eCommerce on the Instagram platform; users can shop via the designated “Shops” tab, purchase tagged products in stories, buy ‘badges’ during IG Lives (in beta now, rolling out worldwide later this year), and more is coming.

We’re also anticipating the release of some kind of Live Selling feature on IGTV this year as well.

Get ahead of the changes

Overall, the algorithm still has the same basic formula at its foundation, but what changes is where Instagram wants to direct a user’s attention at any given time. Right now, it’s video and Reels. Use that information to formulate your content and influencer marketing strategies, allocating more budget for video content over Feed Posts.

As the year progresses, expect that you’ll need to adjust your strategy to include more in-app shopping opportunities. As the Shops feature matures and Instagram continues to expand its eCommerce offerings, purchasing history will become an even more heavily weighted factor in the 2021 Instagram algorithm.

Want to know how Allegiant Media helps brands, agencies and creators discover and connect with the perfect creators for their campaigns?  Get in touch and we’ll show you how!

This article was originally featured on on January 26, 2021.