PostEaseThe short answer
A Reel is a short vertical video on Instagram or Facebook, made to be watched full screen and shown to people who do not follow you as well as to those who do. Instagram Reels are uploaded at 1080 × 1920 (9:16) and can run up to 20 minutes, though Instagram says reels over 3 minutes are not recommended to new audiences.
Reels are the format for reaching new people. Buffer’s 2026 engagement report found Reels reached about 1.36 times as many people as carousels, while carousels earned roughly twice the engagement rate. Instagram says it ranks Reels most on whether a viewer will reshare one, watch it all the way through, like it, and open its audio page.
Reel size and length
The figures, from Instagram’s Help Centre and Meta’s developer documentation:
| What | ||
|---|---|---|
| Size | 1080 × 1920 (9:16) | 9:16, 1080 × 1920 |
| Shapes allowed | 1.91:1 to 9:16; 30 fps and 720 pixels or more | At least 540 × 960; 24 to 60 fps |
| Length | Up to 20 minutes; over 3 minutes is not recommended to new audiences | 3 to 90 seconds, via the API |
| Cover | 420 × 654 (1:1.55); Cannot be edited after upload | — |
What Instagram ranks Reels on
Instagram’s ranking explainer, written by its head Adam Mosseri in 2023, names the most important predictions for Reels: the likelihood that a viewer will reshare a reel, watch it all the way through, like it, and open its audio page. It also says it shows low-resolution, watermarked and already-posted reels less, so a video exported from another app with its logo on it starts behind.
Reels against other formats
Reels win on reach beyond your followers, and lose among them. Two 2026 studies measured it from different angles:
| Study | Finding |
|---|---|
| Buffer, Instagram, 2026 | Reels reached about 1.36 times as many people as carousels; carousels earned roughly twice the engagement rate |
| Socialinsider, Facebook Pages, 2026 | Reels reached about 0.55% of a Page’s followers per post, against 1.20% for images |
Making Reels that work
Read the ranking signals as a checklist:
- Start with the point, so the first seconds are worth staying for.
- Keep it as short as the idea allows, so more people watch to the end.
- Make it worth sending to one person: useful, funny or surprising.
- Upload your own clean file, not one carrying another app’s watermark.
- Post it to Reels and plan carousels for the followers you already have.
Questions
How long can a Reel be?
Up to 20 minutes on Instagram, though Instagram says reels over 3 minutes are not recommended to new audiences. Facebook Reels published through Meta’s API run 3 to 90 seconds.
What size is a Reel?
1080 × 1920 pixels, a vertical 9:16 shape, on both Instagram and Facebook.
Do Reels get more reach than posts?
Beyond your followers, yes: Buffer found Reels reached about 1.36 times as many people as carousels. Among your followers, other formats can do better; carousels earned roughly twice the engagement rate.
Why does Instagram show some Reels less?
Instagram says it shows low-resolution, watermarked and already-posted reels less. Upload a clean, sharp file made for Reels.
Sources
- Instagram, Reel size and aspect ratios on Instagram, checked October 2026.
- Instagram, Instagram ranking explained, May 2023.
- Buffer, The state of social media engagement in 2026, March 2026.
- Socialinsider, Social media reach has a 14% YoY decrease on Instagram, September 2026.
- Meta, Reels publishing, Video API, checked October 2026.