How does the Instagram algorithm actually work? It’s a question that’s caused a lot of confusion since Instagram moved away from a chronological feed. 

In this article, we’ll share how the Instagram algorithm works for feed posts, stories, the Explore page, IGTV videos, and Reels.

Plus, discover the top tips to hack the Instagram algorithm, so you can get more engagement for your business or brand.

Design Principle

Ever since Instagram ended the reverse-chronological feed back in 2016, every person’s feed on the platform has been organized according to the algorithm’s rules.

Before instagram launched a new feed called “Suggested Posts”, it already had two different ranking systems: 

  1. The Home Feed Ranking System ranks the posts from the sources you follow based on factors like engagement, relevance, and freshness. 
  2. On the other extreme lies the Explore Ranking System, which opens you up to many other public posts that might be relevant and engaging to you

Last August 2020, Instagram’s found a new way to keep you hooked on scrolling — the Suggested Posts feature! Normally when you get to the end of your feed, Instagram simply displays a ‘You’re all caught up!’ message and lets you view older posts. Instead, after said message, you’ll now see suggested posts from other accounts by default – including ads, of course.

These posts, from accounts you don’t follow, will show up after you’ve reached the end of your feed and give you the option to keep scrolling with Instagram’s suggestions.

This new ranking system was designed by instagram so that the user will be able to have a more personalized Instagram feed and make them feel like they crafted these recommendations themselves. 

System Overview

Before we dive into the details of the machine learning system – on how Instagram designed this marriage of familiarity + exploration. It is necessary to state the design principles which shall guide us along the way.

The following flowcharts display the key difference between a connected recommendation system versus an unconnected recommendation system. 

In a connected recommendation system, like Instagram Home Feed or some popular subscription-based news reader, the sources are explicitly defined by the end user. The ranking system picks the best posts provided by these sources and ranks them based on factors like engagement, relevance, user interests, content quality, and freshness. 

In an unconnected system (like Suggested Posts), sources are derived implicitly based on a user’s activity across Instagram and are then ranked based on similar factors.

Candidate Generation

In the first step of candidate generation, based on a given user’s explicit or implicit interests we fetch all the candidates that a user could be possibly interested in.

A user’s activities on Instagram helps us in building a virtual graph of their interests as shown below. Every node in this graph can now be a potential seed. The seed accounts are usually only a fraction of the accounts on Instagram that are about similar or the same interests. 

Each seed can now be used as an input in Instagram’s K-nearest neighbor pipelines which output similar media or similar authors.

Cold Start Problem

Many new (and some seasoned) users may not have enough recent engagement on Instagram to generate a big enough inventory of candidates for them. This brings us to the familiar situation of dealing with a cold start problem in recommendation systems. Instagram deals with the problem in the following two ways:

  1. Fallback graph exploration: If a user A hasn’t liked a lot of other accounts, Instagram evaluates the accounts followed by the accounts A has liked and considers using them as seeds. A → Account Liked by A → Accounts followed by the accounts A likes (Seed Accounts). The diagram below visualizes this line of thinking.
  2. Popular media: For extremely new users, Instagram’s algorithm typically gets them started with popular media items and then adapts its parameters based on their initial response.

Candidate Selection

In the second stage of candidate selection, typically a more heavy-weight ranking algorithm works on these candidates and selects the best subset that is finally shown to a user. 

With different types of sources, Instagram is able to find tens of thousands of eligible candidates for the average person. Using a variety of signals, instagram filters out content that they can identify as not being eligible to be recommended before they build out eligible inventory for each person.With this, the suggested posts feed follow the same freshness and time sensitivity heuristics as Home Feed to ensure that Suggested Posts will provide a similar kind of fresh feeling as the rest of Home Feed.

Instagram wants to assure the users that the mixture of media types (like photos/videos/albums etc.) are relatively similar in Home Feed and Suggested Posts. Finally, since they receive regular qualitative guidance from user experience researchers and user surveys a Home-like feeling in suggested posts was made possible.

The Instagram Algorithm

After creating the key building blocks necessary to experiment easily, identify people’s interests effectively, and produce efficient and relevant predictions, Instagram combined these systems together in production.

If you’ve spent any time on Instagram, you’ll know that the algorithm can behave in mysterious ways. But once you understand how the elusive algorithm actually works, you can tailor your content strategy to work alongside it.

Ready to get up to speed on the Instagram algorithm in 2021? Here’s everything you need to know:

Table of Contents: 

  1. How the Instagram Algorithm Works for Feed Posts in 2021
  2. How the Instagram Algorithm Works for Instagram Stories
  3. How the Instagram Algorithm Works on the Explore Page
  4. How the Instagram Algorithm Works for IGTV Videos and Reels
  5. 7 Extra Ways to Improve Your Ranking with the Instagram Algorithm

How the Instagram Algorithm Works for Feed Posts in 2021

According to Instagram, there are 6 key factors that influence the Instagram algorithm for feed posts:

  1. Interest
  2. Relationship
  3. Timeliness
  4. Frequency
  5. Following
  6. Usage

Factor #1: Interest

Your Instagram feed isn’t only based on who you follow, it’s also based on the accounts and types of posts you’ve liked historically. The more the Instagram algorithm thinks you will “like” a certain type of post, the higher it will appear in your feed.

Basically, what you see in your Instagram feed is a combination of all of your Instagram behaviors. The accounts you interact with the most, the people you are tagged in photos with, and of course, the type of posts that you like and comment on.

This is why consistently showing up on Instagram is so important. It sends positive signals to the Instagram algorithm — and gives your audience more opportunities to interact with your content. 

What Engagements Are Most Important to the Instagram Algorithm?

When it comes to feed performance, we know the algorithm prioritizes content that receives the most engagement. But what are the most important metrics of engagements?

According to Instagram, the most important engagements for feed ranking are comments, likes, reshares, and views for videos, which is really helpful to know as you plan your content and captions.

Although it’s not listed as a key engagement indicator at the moment, it could also be worthwhile to optimize your content for saves — especially as Instagram trials hiding likes in more countries

Factor #2: Relationship 

The Instagram algorithm wants to prioritize posts from your friends, family, and accounts that you care about.

So in order for Instagram to show you what you want (what you really, really want), the algorithm uses your interactions to piece together who is closest to you.

Thomas Dimson, a software engineer at Instagram, shared how Instagram could theoretically figure out whom you care about the most, based on how you use the app:

  • People whose content you like (possibly including stories and live videos)
  • People you direct message
  • People you search for
  • People you know in real life

Instagram will try to calculate this relationship (and your interest level) as soon as you follow someone by serving you their content and monitoring how you engage with it.

Factor #3: Timeliness

Not only does the algorithm pay attention to how much engagement your Instagram post gets, but it also looks at how long ago the photo was posted.

Instagram’s algorithm cares about when you posted, because it always wants to serve you the latest, most interesting posts.

By finding your personalized best time to post on Instagram, you can hack the algorithm to increase your reach and get more likes and followers. And if you post at a time when your followers are online and most active, you give yourself a better chance of getting more likes.

Factor #4: Frequency 

How often do you open the Instagram app? If you’re a frequent scroller, your feed will look more chronological, since Instagram tries to show you the best posts since your last visit.

If you check the Instagram app less often, your feed will be sorted into what Instagram thinks you’ll like, instead of chronologically.

Factor #5: Following

How many people do you follow on Instagram? If you follow a lot of people, then Instagram has more options to choose from, so you probably won’t see all of the posts from every account.

On a related note, it could be worth systematically removing inactive or “ghost” followers.

If a large percentage of your following is inactive, they could be doing more harm than good for your account’s algorithmic ranking.

Factor #6: Usage

If you spend a lot of time on Instagram, you’re going to see more posts as Instagram digs deeper into its catalog.

If you spend enough time on Instagram, you can even run out of new content to see. Once this happens, the algorithm will serve you suggested content from new accounts — based on your previous interactions.

However, if you only spend a few minutes in the app each day, then you’re going to just get the day’s highlights from the algorithm.

How the Instagram Algorithm Works for Instagram Stories

Typically, Instagram Stories that appear at the start of your feed are from accounts that you engage with the most, whether that’s through likes, comments, story views, reactions, or DMs.

The Instagram algorithm in 2020

The Instagram Stories algorithm also puts a lot of focus on timeliness, as it wants to make sure it’s always showing you the latest stories from your favorite accounts.

If you regularly engage with an account, their new stories will be bumped to the front of your feed every time they post — even if you’ve watched all their stories from the previous day.

So with this in mind, it’s a good idea to consistently post to Instagram Stories.

How the Instagram Algorithm Works on the Explore Page

Overall, the Explore page and the feed algorithm are quite similar — they both deliver content that Instagram thinks you’ll be most interested in, based on your prior interactions.

However, your Instagram feed will be made up of content from accounts you already follow, whereas the Explore feed will consist almost entirely of content from new accounts.

The Explore page is constantly evolving, with new topic categories and advanced search functionalities being introduced all the time. For example, you can now search by keywords, as well as hashtags, to discover feeds of relevant content:

everything you need to know about instagram algorithm

This suggests that the Explore page algorithm takes into account way more than just the tags on your posts, such as the actual visual content and words in your caption.

Fortunately, getting your posts onto the Instagram Explore page isn’t as hard as you might think.

The Explore page algorithm is essentially trying to serve people the best, relevant content. So by continually sharing great content with strong captions and niche hashtags, you’re already contributing towards your Explore page ranking.

For hashtags search results, Instagram prioritizes top performing posts:

the instagram algorithm in 2021

These posts are selected based on engagement (how many likes and comments the post received) and the amount of competition for the hashtag.

Search results will be the same for every user searching a specific hashtag, while the main Explore page is tailored to your individual interests.

How the Instagram Algorithm Works for IGTV Videos and Reels

For IGTV videos and Instagram Reels, the algorithm prioritizes content from the accounts you interact with the most, as well as the type of posts you typically engage with.

Beyond the home feed, Instagram serves suggested IGTV videos and Reels in relevant Explore pages, including the new Reels tab.

This is based on what Instagram thinks you will like, based on a machine learning model.

everything you need to know about the instagram algorithm

So how can you give your IGTV videos and Reels the best chance of being seen by new (and existing) audiences?

The trick is to give them as much of a helping hand as possible.

For IGTV videos, you can share a 1-minute preview to your Instagram feed — increasing initial exposure and providing a positive signal to the algorithm.

this is how the instagram algorithm works

For Reels, always share them to your main Instagram feed, and include several hashtags to boost their discoverability.

7 Extra Ways to Improve Your Ranking with the Instagram Algorithm

If you want to improve your ranking with the Instagram algorithm, the best thing you can do is drive as many interactions (likes, comments, DMs, saves, and shares) as possible.

And by building momentum with your existing community, you’ll soon find your content is being surfaced to new audiences.

Here are 7 ways to improve your algorithmic ranking and reach new audiences:

#1: Embrace Instagram’s Latest Features 

Looking for a fast-track way to gain favor with the Instagram algorithm?

Embrace Instagram’s latest features!

Instagram will always give their latest features (such as Instagram Reels) a helping hand to help drive adoption, so it’s a good idea to jump on the latest trends and take advantage of this extra boost.

#2: Encourage More Interactions with Instagram Stories Stickers 

Instagram Stories stickers are a great way to encourage audience engagement — and the more engagement your posts get, the higher they’ll be boosted by the Instagram algorithm.

There are lots of Instagram stickers, but the best ones for driving engagement are the poll, emoji slider, and question stickers.

Poll and emoji slider stickers are a quick and easy engagement win, and can work for almost any business or brand.

Question stickers may not be as quick to take part in, but they can be just as good at driving genuine engagement with your audience, which is highly valuable for the Instagram algorithm.

#3: Drive Conversations with Engaging Captions and Comments   

Instagram has confirmed comments are super important when it comes to feed ranking — so it’s a great idea to encourage as many as possible for your posts.

One of the best ways to do this is by writing good captions that drive engagement including a call-to-action in your Instagram caption can go a very long way when it comes to driving more interactions.

This could be as simple as asking your followers to share their thoughts or feelings, double-tap if they agree, or tag a friend in the comments.

Looking to level-up your conversational captions? Check out our blog post: The Ultimate Guide to Writing Good Instagram Captions!

#4: Optimize Your Hashtag Strategy

Adding hashtags to your posts is one of the most effective ways to reach more people on Instagram, which means more “views” for the Instagram algorithm to take into account.

And with a good hashtag strategy, you won’t just reach more people — you’ll reach people who are relevant for your business, and most likely to engage with your content.

#5: Cross-Promote Your Instagram Content 

If you’re looking for a quick and easy engagement win to help boost your algorithm ranking, cross-promoting your Instagram content is a great place to start.

As Instagram has grown, so too has the number of channels that you can share content: feed, stories, IGTV and Reels.

And thanks to these different publishing channels, you can strategically use them to drive different audiences to your most recent content.

the instagram algorithm in 2021

This could be as simple as sharing an enticing preview of an IGTV video to your feed, or even adding a feed post to stories with a “Tap Here” GIF.

#6: Keep On Top of Your DMs

Much like comments and likes, direct messages (DMs) are a strong engagement indicator for the Instagram algorithm.

You may have noticed that the accounts you DM most often are bumped to the front of your Instagram Stories feed — the Instagram algorithm is doing it’s best to serve you content it thinks you want to see.

One way to use this to your advantage is to regularly invite your audience to DM you with their questions or feedback — or by encouraging “quick emoji reactions.”

#7: Use Instagram Analytics to See What’s Working

Tracking and monitoring how your content is performing on Instagram is one of the most reliable ways to take on the Instagram algorithm.

Having a better understanding of what’s working (and what isn’t) will help you come up with a finely tuned marketing plan, saving you time and effort in the long run.

But diving into your Instagram Analytics means more than just finding out which photo, video, or stories performed best. Truly understanding how your content performs – by tracking key metrics over time – is vital to knowing what helps improve your ranking.


Whatever tactic you choose to focus on to improve your algorithm ranking in 2021, the most important thing is to keep engaging with your audience at the heart of your strategy.

Building a genuine relationship with your followers is the most powerful way to “hack” the algorithm and, most importantly, it will work wonders for your brand too.