How the Instagram algorithm works: what drives reach and how to work with it

Key points

• Instagram has several algorithms, one for each part of the app
• Watch time, likes and sends are the strongest ranking signals, according to Instagram head Adam Mosseri
• Sends carry a little more weight with people who don’t follow you yet
• Instagram favors original content over reposts of someone else’s work
• Shares are the second-largest interaction on brand posts after likes, in Emplifi’s quarterly social media benchmarks

One week a Reel takes off, and the next one barely reaches your own followers. The Instagram algorithm can feel unpredictable, but it isn’t random. Instagram has said in public which signals decide how far a post travels, and people are passing brand posts on: shares are now the most common interaction after likes, according to Emplifi’s Q3 2026 social media benchmarks.

This guide lays those signals out for you, so you can plan posts around them and track the numbers that matter. For the wider picture across networks, see our guide to how social media algorithms work.

How does the Instagram algorithm work?

The Instagram algorithm works as a group of AI systems, one for each part of the app, that predict which posts each person will find most valuable and rank them in that order. Feed, Stories, Reels and Explore each have their own system, and Meta publishes how each one works.

Meta’s explainer for the Instagram Feed AI system says it “automatically orders the posts in your feed by predicting what you will find most valuable and relevant.” The process has four steps:

1. Gather the posts from accounts the person follows (suggested posts and ads are ranked by separate systems), and remove anything that breaks Instagram’s Community Guidelines
2. Look at signals for each post, such as who created it and what type of content it is, and pick about 700 of the most relevant
3. Predict how the person will respond to each one, based on what and whom they’ve followed, liked or interacted with recently
4. Score about 500 posts and show the highest scores first, with a balanced mix of formats

Connected vs. unconnected reach

Instagram ranks content for two audiences: people who follow you (connected reach) and people who don’t follow you yet (unconnected reach). In a video on how ranking works in January 2025, Mosseri said: “For both, the top three signals that matter most for ranking are watch time, likes and sends.” He suggested watching “average watch time, likes per reach, and sends per reach” in Insights, and added that “likes are slightly more important for connected content, and sends are slightly more important for unconnected content.”

Mosseri names the three signals that matter most for ranking.

What signals does the Instagram algorithm rank on?

The Instagram algorithm ranks first on watch time, likes per reach and sends per reach. Originality and your history with each person also feed in, and negative signals can pull a post down.

Sends carry extra weight because a send puts your post in front of someone who may never have seen your account, which is the unconnected reach described above. Meta’s Feed explainer gives a clue about what gets sent: when it predicts how likely someone is to share a post in a direct message, one of the signals is whether the post is informative, such as news, a product review, a tutorial or a how-to.

Originality counts too. In April 2026, Instagram extended its originality rules from Reels to photos and carousels: accounts that mostly post content they didn’t create, or didn’t meaningfully edit, are no longer shown where Instagram recommends content. Their followers still see their posts. Instagram says 75% of recommendations in the US now come from original posts.

Negative signals pull the other way. Meta’s Reels ranking explainer lists how likely someone is to watch less than three seconds of a reel, and its Explore explainer lists how likely they are to tap “Not interested”. Both are predictions the systems use when they choose what to show.

How does each part of Instagram rank content?

Each part of Instagram ranks content with its own AI system.

Feed

Feed ranks posts from accounts a person follows, based on what and whom they’ve liked or interacted with recently, so a follower who often interacts with you is more likely to see your next post. Meta’s Feed explainer lists the predictions behind the order, including how likely someone is to swipe through a whole carousel, how long they’ll spend on a post and how likely they are to send it to someone.

Stories

Stories come only from accounts a person follows, ordered in the row at the top of the app. According to Meta’s Stories explainer, the system looks at how many times someone has viewed your stories, how often they’ve replied to them and how likely you are to be friends or family. It also predicts how likely someone is to answer a question in a story, so a question sticker gives followers an easy reason to reply.

Reels

Reels mixes accounts a person follows with reels similar to ones they’ve recently watched, so a reel can reach people who don’t follow you yet. A first model picks about 100 reels, then the system scores and orders them. Meta’s Reels explainer lists predictions such as how likely someone is to watch more of a reel than 95% of people who watched reels of the same length, reshare it or use its audio in a reel of their own.

Explore

Explore is built for discovery. It gathers posts linked to a person’s interests, narrows them down to 100, then ranks them on predictions of how the person will respond, such as how likely they are to like or save each one. Meta’s Explore explainer also lists how likely someone is to follow the author and to watch more than 95% of a video.

Reposts

Since August 2025, people can repost public reels and feed posts. Instagram recommends reposts to the reposter’s friends and followers, with credit to the original account, so one repost can carry your post to people who don’t follow you. Emplifi’s Q3 2026 social media benchmarks now count reposts as Instagram interactions.

Collabs

Collab posts appear on every co-author’s profile and in front of each co-author’s audience, so one post can reach two communities at once.

How to work with the Instagram algorithm

Work with the Instagram algorithm by giving people a reason to watch to the end and then send the post to someone.

Create net-new, original content

Make your own content for Instagram rather than re-sharing other people’s posts. When you join a trend, add something of yours, such as your own footage, text that adds context or a clear point of view, so the post counts as original. To share a creator’s post, use the repost button or a collab post, which both credit them.

Emplifi pro tip: Open each Reel with the payoff or the question, then explain, so people stay past the first three seconds.

Start a conversation

Ask questions people want to answer, and reply while the thread is active. Community content gives people something to respond to: Delta reshared a creator’s Reel of her father’s last flight as a pilot.

Delta’s reshare credits the creator who filmed it.

Three brands show how the same signals play out:

• Yakima runs the hashtag #yakimaracks and posts outdoor sports such as rock climbing and fly fishing, so fans and outdoor creators make Reels of their own
• Puma keeps niche accounts such as @pumarunning and co-posts Reels across them and with creators, so each post reaches a specific interest group
• Alo Yoga features creators wearing its clothes, tags the products and runs giveaways to draw comments and new followers

Yakima shared a family hiking trip from creator @chasing.sage under #yakimaracks.

Puma’s running account co-posted this Reel about its Deviate 4 running shoe with other accounts.

Alo shows a creator in its Winter ’26 collection.

How do hashtags work with the Instagram algorithm?

Hashtags aren’t dead, but their job has changed. Since December 2025, Instagram allows up to five hashtags on a post or reel, and it says fewer, more targeted hashtags can improve both how content performs and people’s experience on the app, as Social Media Today reported. Mosseri has said hashtags don’t improve a post’s visibility, but they’re “a great way to let people know what a post is about.”

So treat hashtags as labels, not a way to get more reach. Use one clear keyword in your caption and three to five hashtags that describe the post itself. Search each hashtag before you use it, to check it’s the conversation you want to join.

What content formats work best for the Instagram algorithm?

Carousels and Reels earn the most interactions per post, and shares make up more of Reels’ interactions than any other format’s, according to Emplifi’s Q3 2026 social media benchmarks. Images still have a place, since Meta says Feed aims for a balanced mix of formats.

Design Reels to be shared, and use carousels for guides and step-by-step posts that people save. Our Instagram marketing strategy guide covers the full content mix.

Crunch Fitness used Emplifi’s labeling and reporting to see which content types drove the most engagement across its franchise network. With Emplifi, the brand manages 1,300+ social profiles, has 130 franchisee team members on the platform and cut reporting time by 90%. “We’ve learned that Reels are our number one performer, with Carousels coming in second,” said Aminta Iriarte, Social Media Associate Director at Crunch Fitness. Read the Crunch Fitness story.

Crunch Fitness uses format results to guide posts across its franchise network.

What does Instagram’s long-form video test change?

Instagram is testing longer videos. Called Features, they’re horizontal videos of up to 90 minutes, in a test that’s open for now to selected creators. Short Reels clips from a Feature point viewers to the full video, which they can watch on their phone, with TV viewing planned.

If you get access, plan the long video and its clips together. The clips are how people discover the full video: they show up in Reels, where people find them and send them on. Judge each clip on sends per reach, as you would any Reel.

It’s still a test. Instagram leans into long-form video: What it means for brands and creators covers what Mosseri and Instagram’s Tessa Lyons announced.

How do you check your own numbers?

You check your own numbers by setting them next to your industry’s medians, which Emplifi publishes every quarter for each industry and region in its industry benchmarks hub. Start with these:

• Engagement rate per impression, against your industry’s median in the hub
• Shares per post, against the brand medians in Emplifi’s Q3 2026 social media benchmarks
• Sends per reach from your Insights, tracked against your own past months, since Emplifi’s benchmarks count all shares together

Then look at your top 10 posts by reach. If shares make up more of their interactions than on your average post, make more posts like them.

You don’t need to pull these numbers by hand each month. In Emplifi Unified Analytics, Emplifi’s social media analytics platform, a Dynamic Board can track engagement rate per impression and shares per post by format, and you can save the view and schedule it as a regular report. Competitive Benchmarking in the same platform puts your profiles next to competitors and industry peers.

Fuel AI, the agentic intelligence layer built into Emplifi Fuel, analyzes your account data and builds boards from a plain-language request, and it asks for your approval before it creates or deletes anything. Existing Emplifi customers add it through their customer success manager. One example could be: “Compare our Instagram engagement rate per impression and shares per post this quarter with last quarter, by format, and explain what changed.”

Final thoughts: Make posts worth sending

Instagram will keep adjusting how it ranks posts, but the signals it names are simple: people watch to the end, like the post and send it to someone. That’s good news for brands. Reach comes from the work itself, not from tricks.

Start your next content review with sends per reach and watch time. Look at which posts traveled furthest and what they had in common, then make more like them. Keep your content original, and use collabs and reposts to reach new communities.

Then check how you compare. Set your engagement rate per impression against your industry’s median in Emplifi’s industry benchmarks hub each quarter, so you can tell whether a dip comes from your content or from the whole market.

Ready to see how your Instagram engagement compares with your industry? Book a demo with the Emplifi team.