Change Video Speed Online — Speed Up or Slow Down
Change video speed online from 0.5× to 2× while keeping available audio synchronized in a local MP4 export.
Loading local video processor…
About this tool
The tool retimes video presentation timestamps and applies a matching audio tempo adjustment. Choose a slower or faster multiplier, preview the expected duration and export a synchronized H.264 and AAC MP4.
How to use
- Choose a supported local file or enter the required values.
- Review the available settings and run the tool.
- Check the result, then download or copy it before closing the page.
Features
- Continuous speed control from 0.5× to 2×.
- Video and available audio adjusted together.
- H.264 MP4 output generated locally.
Common use cases
- Speed up a screen recording or time-lapse segment.
- Slow down an instructional demonstration.
- Match a clip to a shorter presentation slot.
Common issues and tips
- Speed changes require re-encoding and can reduce quality slightly.
- Extreme speed changes may make speech harder to understand even when synchronized.
Privacy
Your video, image or subtitle data is processed locally in your browser and is not uploaded to Tools12345.
Frequently asked questions
Is audio pitch preserved?
The audio tempo filter changes duration while aiming to avoid a simple pitch shift.
How does 0.5× affect duration?
It makes the output approximately twice as long.
Can I use values above 2×?
The current interface supports 0.5× through 2×.