# Change video speed — slow-mo & timelapse, no upload

> Speed up or slow down a video (0.25×–4×) for slow-motion or timelapse, with live preview and tempo-synced audio. Exports MP4/WebM in your browser, no upload.

Speed up or slow down a clip from 0.25× to 4× for slow-motion or timelapse, with a live preview and audio kept in sync. FFmpeg runs in your browser, so the video isn't uploaded.

Retiming turns ordinary footage into something more deliberate — a slow-motion moment for emphasis, or a timelapse that compresses a long process into seconds. Doing it locally means even personal or unreleased footage stays on your machine.

The live preview lets you feel the pacing before rendering, and keeping audio in sync avoids the tinny drift you get from naive speed changes. To cut the clip down first use Trim video, and to turn a short segment into a loop use the GIF maker.

## How to

1. **Add a video.** Drop the clip you want to retime.
2. **Set the speed.** Choose a rate from 0.25× (slow-mo) to 4× (timelapse) and preview it.
3. **Trim if needed.** Optionally set a clip range before exporting.
4. **Export.** Render MP4 or WebM locally.

## FAQ

### Does slowing a video keep the audio in sync?

Yes. The audio is tempo-adjusted to match the new speed so it stays aligned rather than drifting or dropping out.

### How slow or fast can I go?

From 0.25× for smooth slow-motion up to 4× for a timelapse effect, with a live preview at each rate before you commit.

### Is my video uploaded to change its speed?

No. Retiming runs through FFmpeg in your browser tab, so the footage never leaves your device.


## Related tools

- [Trim & mute](https://www.safepaper.app/media/trim-video)
- [GIF maker](https://www.safepaper.app/media/gif-maker)
- [Transcode](https://www.safepaper.app/media/video-converter)
- [Normalize audio](https://www.safepaper.app/media/audio-normalize)

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Canonical HTML: https://www.safepaper.app/media/video-speed
Markdown: https://www.safepaper.app/media/video-speed.md

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