How long should a TikTok, Reel or Short be?
Ideal short-form video length by platform and goal — when 7 seconds beats 60, why completion rate matters more than watch time, and how to choose.
“How long should my video be” is really two questions: what does the algorithm reward, and what does your idea need? The honest answer — the shortest cut that completes the idea — sounds like a dodge, so let’s make it concrete.
What the platforms actually reward
Short-form ranking leans heavily on completion and rewatch, not raw watch time. A 9-second video watched 1.5 times on average beats a 45-second video abandoned at 60%. That asymmetry is why ultra-short clips keep going viral and why padding is the most expensive mistake in short-form.
- 7–15s — the loop zone: single joke, single reveal, single before/after. Highest rewatch potential, weakest for trust-building.
- 20–35s — the sweet spot for tutorials, product demos and storytimes with one twist. Long enough for proof, short enough to complete.
- 45–90s — earns its length only with strong narrative pull; expect lower completion but deeper engagement (comments, saves, follows).
Choose by goal, not by habit
- Reach — cut to the loop zone; trim until removing one more second breaks the idea
- Conversion — 20–35s: hook, problem, one proof moment, soft CTA (see our UGC ads guide)
- Audience-building — longer is fine if every 5-second block earns the next; structure it with the 3-beat script
The right length is the shortest version that completes the idea — then one second shorter than feels comfortable.
Length norms also drift with trends — formats themselves carry an expected duration. Admetra’s trend breakdowns show the typical cut length for each rising format, so you start from what the format expects instead of guessing.