Instagram's algorithm underwent significant changes in 2025, with head Adam Mosseri confirming in January that watch time, likes per reach, and DM shares are the three most important ranking factors. Combined with September's rollout of algorithm reset tools and reaching 3 billion monthly users, marketers need to understand both how to optimize content AND how to control their feed for competitive research.

How Instagram's Algorithm Actually Works in 2025

Instagram officially abandoned the singular "algorithm" terminology in 2025. Instead, the platform uses multiple AI-powered ranking systems: one for Feed, another for Stories, separate ones for Reels and Explore. Each makes thousands of predictions about what you'll engage with.

But across all these systems, three signals matter most (confirmed by Adam Mosseri, January 2025):

The 3 Critical Ranking Factors

1. ‍Watch Time (Most Important) How long people watch your content, especially Reels. Instagram heavily weighs whether viewers watch past the first 3 seconds, research shows viewers decide within 1.7 seconds whether to continue watching.‍
2. Likes Per Reach The percentage of viewers who like your post. This matters more for your existing followers than for reaching new audiences.‍
3. Sends Per Reach How often people share your content via DM. This is the most powerful signal for reaching new audiences because sharing indicates strong enough value to recommend to someone you care about.

Key distinction: For reaching your existing followers, likes matter slightly more than shares. For discovery and viral growth through Explore/Reels, shares matter more than likes.

Content Eligibility Requirements

Before Instagram even considers ranking your content for recommendations (Explore, suggested posts, non-follower Reels), it must meet these five criteria:

1. No watermarks from other platforms (TikTok, CapCut)
2. Must include audio (music or voiceover)
3. Videos under 3 minutes in length
4. Original or transformed content, not just reposts
5. Account in good standing (check Settings → Account Status)

Content violating these rules can stay on Instagram and be seen by followers, but won't be recommended to new audiences.

2 Key Instagram Algorithm Updates in 2025

Update 1: Algorithm Reset & Topic Controls (September-October 2025)

Instagram launched the recommendation reset feature globally in fall 2025, alongside topic-based controls. Settings → Content preferences → Reset suggested content wipes your entire algorithmic history across Explore, Reels, and suggested posts. Within 24-48 hours, the algorithm starts fresh based on your new behavior.

The topic controls (testing in October 2025) appear in Reels settings → Your Algorithm. You'll see topics Instagram thinks you're interested in with simple on/off toggles, like "Film photography," "Skincare," or "AI tools."

When to reset: Agency accounts managing multiple industries with mixed signals, you pivoted business focus (B2C to B2B, restaurant to SaaS), or your Explore page is fundamentally broken for competitive research.

Pro tip: After resetting, immediately spend 15-20 minutes engaging only with industry-relevant content to train the fresh algorithm correctly.

Update 2: Small Creator Boost & Non-Follower Testing (Ongoing Impact)

Instagram now prioritizes original content from smaller creators over reposts and aggregator accounts. The platform labels reposted content and penalizes accounts that repeatedly post others' content without transformation.

Additionally, Instagram shows Reels to random non-followers first to gauge broader interest before showing them to your existing audience. If your Reels get high watch time and engagement from non-followers during testing, Instagram pushes them harder to your followers and beyond.

How to Optimize for Instagram's 2025 Algorithm

Tactic 1: Nail the First 3 Seconds

With watch time as the #1 ranking factor and a 3-second retention threshold, your hook determines everything. 94% of Instagram distribution now comes from AI recommendations—the algorithm won't push content people immediately skip.

Effective hooks:

• Start mid-action (not with slow introductions)
• Use pattern interrupts (unexpected visuals/statements)
• Front-load the payoff (tell them what they'll learn immediately)
• Test different hooks on the same content using Trial Reels

Tactic 2: Design for DM Sharing

Instagram's algorithm considers sends via DM the strongest signal for reaching new audiences. According to Metricool data, 694,000 Instagram Reels are sent via DM every minute.

Make content shareable by:

• Creating "send this to someone who..." moments
• Including relatable situations people tag friends in
• Providing value worth recommending (tutorials, insights, tools)
• Using Story stickers that prompt DMs and replies
• Adding caption CTAs like "Share this with your team"

Track "Sends" in Instagram Insights under individual post metrics to identify what resonates enough for people to share.

Tactic 3: Optimize Format by Audience Goal

• ‍For reaching existing followers: Carousels and photo posts perform well. Carousel posts now allow up to 20 images and achieve 10.15% average engagement rate (2025 data).‍
• For discovery and new audiences: Reels dominate. Average Reels engagement rate is 1.23% versus 0.70% for image posts.‍
• For deepening relationships: Stories drive intimacy. Accounts under 10,000 followers saw a 35% increase in Story reach rates in 2025. Optimal length is 6-13 slides.

Tactic 4: Understand Connected vs. Unconnected Reach

Instagram distinguishes between two types of reach, and optimization differs:

• ‍Connected reach (your followers): Prioritize consistency, community management, and engagement. Reply to comments quickly, respond to DMs, foster conversation. The algorithm rewards accounts that actively engage their community.‍
• Unconnected reach (discovery): Prioritize shareability, hook strength, and watch time. Use trending audio, optimize for the first 3 seconds, create content worth sending to non-followers.

Most accounts need both, but newer accounts should skew 70/30 toward unconnected reach tactics until they build an audience.

Tracking What Actually Matters

The metrics that align with Instagram's ranking factors:

Primary metrics:

• Average watch time (for Reels/videos)
• Engagement rate (likes + comments + saves + shares / reach)
• Shares via DM (tracked per post in Insights)
• Impressions from non-followers (discovery indicator)

Secondary metrics:

• Profile visits from recommended content
• Follower growth rate (7-day and 30-day)
• Save rate (strong intent signal)

Pull these from Instagram Insights under "Accounts reached" → "Other." For agencies managing multiple client accounts, you can export manually from Meta Business Suite or automate with tools like Dataslayer to consolidate Instagram metrics alongside other platforms in Google Sheets or Looker Studio.

Performance benchmarks (2025):

• Average engagement rate: 0.50% (down 28% year-over-year)
• Accounts under 10K followers: 8-10% like-to-follower ratio
• Accounts over 100K: 3-4% like-to-follower ratio

If you're hitting these numbers, the algorithm is working in your favor.

FAQ Section

What's the most important Instagram ranking factor in 2025?

Watch time is the #1 ranking factor, confirmed by Adam Mosseri in January 2025. How long people watch your Reels matters more than likes or shares for initial distribution. However, secondary factors vary by reach type: likes per reach matters more for existing followers, while DM shares matter more for reaching new audiences. The critical threshold is the first 3 seconds—Instagram heavily weighs whether viewers continue watching past this point.

How do I get my Instagram posts seen by more people?

Focus on Instagram's three priority signals: watch time, likes per reach, and sends per reach. Create Reels with strong hooks in the first 3 seconds (aim for 60%+ retention), encourage DM shares by making content worth recommending, and maintain high engagement rates. Ensure content meets eligibility: no watermarks, includes audio, under 3 minutes, and original. Post consistently, reply to comments quickly, and use Reels for discovery and carousels for existing followers.

Should I reset my Instagram algorithm?

Only reset if your Explore/Reels feed is fundamentally broken—like agency accounts with mixed industry signals or if you pivoted business entirely. Resetting wipes your algorithmic history, which can hurt if you've trained it well. For minor adjustments, use topic controls (Reels settings → Your Algorithm) instead. If you reset, immediately spend 15-20 minutes engaging only with industry-relevant content. Don't reset more than once per quarter or mid-campaign.

Do DMs really help Instagram reach?

Yes—DM shares are one of the top 3 ranking factors and the most powerful signal for reaching new audiences, per Mosseri's January 2025 statements. Instagram interprets DM shares as the strongest endorsement because you're actively recommending content, not just passively liking. 694,000 Instagram Reels are sent via DM every minute (Metricool, 2025). Create "send this to someone who..." moments and track "Sends" in Instagram Insights to identify shareable content.

How long should my Instagram Reels be in 2025?

For new audiences: under 30 seconds. For existing followers: 30-90 seconds. Analysis of 31 million posts shows shorter Reels perform better for discovery because they're easier to watch completely, and completion rate influences algorithmic distribution. Maximum recommended length is under 3 minutes—anything longer becomes ineligible for recommendations. The most critical factor isn't length but retention: keep viewers past the first 3 seconds regardless of duration.

Final Thoughts

Instagram's 2025 algorithm prioritizes watch time, engagement quality, and shareability over vanity metrics. The September-October updates (recommendation reset, topic controls, and continued emphasis on original content) give marketers both optimization paths (improve YOUR content's reach) and curation tools (improve YOUR feed for research).

Start here:

1. Audit your last 10 Reels for 3-second retention and watch time
2. Track which posts get shared via DM most frequently
3. If your Explore feed is broken, reset it (Settings → Content preferences)
4. Experiment with hooks, formats, and shareability tactics
5. Measure results against the metrics Instagram actually cares about

Need to track Instagram performance across multiple accounts or combine it with other platform data? Try Dataslayer free for 15 days to automate your Instagram reporting in Google Sheets, Looker Studio, BigQuery, or Power BI—so you can spend less time pulling metrics and more time optimizing content.

The algorithm rewards creators who understand what it values, and in 2025, that's content people want to watch completely and share with others.