How Long Should a Reel Be? Instagram, TikTok and Shorts

Maximum allowed is not the target

Instagram now permits Reels of up to 20 minutes, raised during 2026 from the previous three-minute cap. That number is close to useless as a guide. Every platform permits significantly longer short-form video than performs well, and treating the limit as a target is one of the most common reasons brand reels underperform.

Upload limits move, so re-check the current figure in the app before planning a format around it. The recommendation below does not depend on the limit, because the limit was never the constraint.

The three-minute discovery cliff

This is the single most useful thing to know about Reels length, and it is not a completion-rate argument. Reels running longer than about three minutes are largely not surfaced to people who do not already follow you. It follows from how the system ranks: Instagram's own ranking explainer describes reels distribution as driven by predicted reshares and completed watches, and a long reel is worse at both.

That changes what the decision is. Under three minutes, a reel can reach strangers through Explore and the Reels tab. Over it, the reel stays mostly inside your existing follower graph and behaves like a post to your own audience rather than a piece of reach. Both are legitimate, but they are different jobs, and it is worth choosing deliberately rather than discovering it afterwards.

Choosing length before you write, not after

Length is a brief decision, not an edit decision. Deciding afterwards is how a 20-second idea becomes a 90-second reel: the material expands to fill whatever runtime nobody set. Pick the job first, reach or depth, and the ceiling follows from it. A reach reel gets one idea and a hard stop. A reel for existing followers can take the time the idea genuinely needs, because the discovery cliff no longer applies to it.

Whatever length you choose, the frame is fixed: Instagram publishes reel size and aspect ratio guidance at 1080 by 1920, 9:16. Shooting or generating to that from the start avoids the crop that quietly removes the bottom of your own captions.

When a longer reel is the right call

Length is not a virtue in either direction. A reel aimed at people who already follow you, answering a question they actually asked, can run past a minute without penalty. The discovery cliff only matters when reach is the job. Tutorials, process walkthroughs and founder explanations are the usual cases, and cutting them to thirty seconds to satisfy a rule of thumb makes them useless rather than punchy.

The test is which audience the reel is for. Reach reels get a hard ceiling; depth reels get the time the idea needs. Publishing both is normal, and the mistake is applying one set of rules to both. Consistent reels versus viral covers how the two fit in a monthly plan.

The related decisions are cadence and consistency rather than duration: how often a brand should post reels and why consistency beats one viral reel both matter more than any single runtime. If reach has fallen off a cliff recently, why your reels stopped getting views diagnoses that separately. We produce these as monthly sets through our social media reels service.

Why completion rate is the real metric

Short-form algorithms reward videos people finish, and reward loops and rewatches more still. A 20-second video finished by half your viewers outperforms a 60-second video finished by a tenth of them, even if the longer one had more total watch time.

This is why cutting a reel down often increases its reach. You are not removing content, you are raising the percentage of people who reach the end.

The two-second rule

A reel does not fail at the end. It fails at second two. By then the viewer has decided, usually without noticing. Everything after that is delivery on a promise the hook already made. Writing that opener is its own craft: see writing a reel hook that holds.

• No logo, no title card, no "hi guys". Three seconds gone before anything happened.
• Open mid-action or mid-sentence. The context can arrive at second four.
• Put the most visually surprising frame first, not in the middle.
• Assume no sound. Captions must carry the hook alone.

How to cut a long reel down

• Delete the introduction entirely. Start at what used to be second four.
• Remove every pause between sentences. Silence in short-form reads as dead air.
• Cut any shot that repeats information another shot already gave.
• Move the payoff earlier and let the explanation follow it.
• End on the last useful frame. No outro, no subscribe card, no fade.

In our own edit suite a first cut usually gives up about a third of its runtime to those five passes without losing a single idea.

The same runtime means different things per platform

A single length does not travel cleanly across the three. YouTube classifies square or vertical video up to three minutes as a Short, so a 150-second cut is short-form there while sitting past Instagram's non-follower discovery cliff. The practical consequence is that the ceiling should be set by the platform you are optimising for, and a cut built for Reels reach will always be safe on Shorts. The reverse is not true.