Every platform publishes a maximum length; none of them publish the number that matters, which is what their ranking systems reward. That number is completion rate — and it's why the practical sweet spot sits far below every official cap.
The limits and the sweet spots
| Platform | Max length (2026) | Practical sweet spot |
|---|---|---|
| TikTok | 10 min (60 min for some accounts) | 21–34 s entertainment · 45–90 s value/how-to |
| Instagram Reels | 3 min | 30–60 s |
| YouTube Shorts | 3 min | 30–50 s |
| X (Twitter) | ~2:20 organic | 20–45 s |
| LinkedIn feed video | 15 min | 45–90 s |
Two patterns explain the table. Entertainment compresses; value stretches. A joke supports 25 seconds; a how-to earns 90 if every second delivers. And professional contexts tolerate length — LinkedIn viewers finish a 90-second insight that would die on TikTok.
Completion beats duration
Short-form ranking overwhelmingly favors watch-through: a 30-second clip watched to the end (and looped) outranks a 3-minute clip abandoned at 40 %. Practical consequences when you're cutting:
- Cut to the content's natural length, then subtract. Whatever feels complete, trim the last 10 % — clips should end a beat early.
- The first 2 seconds are half the battle. Retention graphs cliff at the open; start mid-action (in-point on the payoff's setup, not the preamble).
- Loops count. Under ~35 seconds, an ending that flows back into the opening earns >100 % completion on TikTok and Reels.
One source, several lengths
Since the platforms disagree, cut once and version. With the video splitter's clip queue this is one session: mark the tight 30-second core as one clip, the 75-second full-context version as another (they can overlap on the timeline), export both, and post each where it fits. The 30 s cut goes to Reels/Shorts/TikTok; the longer cut to LinkedIn or X.
When long clips are right
Sweet spots are defaults, not laws. Ship the longer cut when the entire arc is the value — a demo where the payoff needs its setup, a story whose ending only lands with the beginning, a tutorial where skipped steps break trust. A 3-minute clip with 70 % completion is a better signal than a 30-second clip that loses viewers by cutting the reason to care.
The honest workflow: clip generously, post variants, and let each platform's retention data tell you where your audience's ceiling is. Cutting variants costs minutes in the browser-based splitter — no upload queue, no re-render wait, footage never leaves your device.