Shrink or Stretch All Clips to a Target Duration

The Timeline Fitter adjusts all clips on your timeline proportionally so they add up to a specific total duration. If your timeline runs 90 seconds but you need it to be exactly 60 seconds, the fitter trims each clip by the same proportion — preserving the relative balance between clips while hitting your target.

This works in both directions: shrink a long timeline down, or stretch a short one out to fill a required length.

How to Use

1

Open Timeline Fitter

With your project open, tap the fitter tool in the timeline toolbar. A panel appears showing your current total duration.

2

Set a target duration

Enter the duration you want your timeline to be. You can type an exact value or use the preset buttons for common platform limits.

3

Apply

Tap apply. Bitcut recalculates each clip's duration and updates the timeline. Every clip is adjusted proportionally — a clip that was twice as long as another stays twice as long after fitting.

How the Algorithm Works

The fitter divides the target duration equally among all clips as an initial goal. Then it applies proportional scaling so each clip's share of the total stays the same as before.

  • Proportional scaling — a 30-second clip and a 10-second clip, fitted to half their total, become 15 seconds and 5 seconds. The 3:1 ratio is preserved.
  • Minimum clip duration — no clip is shortened below a minimum threshold. If proportional scaling would push a clip below the minimum, that clip is locked at the minimum and the remaining budget is redistributed among the other clips.
  • Stretching — when the target is longer than the current timeline, clips are extended proportionally. Each clip grows toward its full source length but won't exceed it.
Non-destructive: Fitting trims clips the same way manual trimming does. Your original video files are untouched, and you can always undo the fit or adjust clips individually afterward.

Common Use Cases

Platform Duration Limits

Different platforms enforce different maximum lengths. Use the fitter to quickly match your content to the right format:

  • YouTube Shorts — 60 seconds maximum
  • Instagram Reels — 90 seconds maximum
  • TikTok — 60 seconds (standard) or up to 10 minutes

Tightening a Rough Cut

After placing clips on the timeline, you might find the total duration is longer than you want. Instead of trimming each clip one by one, set a target and let the fitter handle the math. Then fine-tune individual clips as needed.

Matching a Music Track

If you've added a music track that is 45 seconds long, fit your clips to 45 seconds so the video and music end together.

What to Watch For

Aggressive targets may remove clips: If the target duration is very short relative to the number of clips, some clips may be too short to keep. In extreme cases, the fitter may need to remove clips entirely to reach the target. Review your timeline after fitting to make sure all important clips are still present.
  • Subtitles adjust automatically — when clips are shortened, subtitle visibility updates to match the new clip boundaries. No manual subtitle editing is needed.
  • Transitions are preserved — existing transitions between clips remain in place after fitting. If a clip becomes very short, check that the transition duration doesn't exceed the clip length.