Change Video Speed — 0.5× to 2×, Free
Change video and audio playback speed together and encode a new MP4. This can provide a faster review copy or a slower view of an action, without creating newly captured source frames.
- Runs in your browser
- Nothing is uploaded
- No signup; device limits apply
How to use this tool
Choose 0.5, 0.75, 1.5 or 2 times speed. Test speech intelligibility on a short section, and adjust any separate subtitle file independently because its timestamps are not retimed here.
Results and examples
Check duration, speech and synchronization in the output. Double speed roughly halves the duration and half speed doubles it, but slowing a clip does not make it equivalent to footage originally captured at a high frame rate.
Worked example
A twenty-second video at 2× runs for approximately ten seconds with audio tempo adjusted too. A twelve-second demo at 0.5× runs for about twenty-four seconds; review caption timing and motion.
Limitations
- H.264/AAC re-encoding and time-axis changes do not guarantee identical frame or audio quality.
- Separate subtitle files and external timecodes are not updated automatically.
Fields
| Field | Guidance and constraints |
|---|---|
| Speed | 0.5× slow / 0.75× / 1.5× / 2× |
Data handling
Processing stays in the current browser tab; the site does not upload tool input for the calculation itself.
Sources
Frequently asked questions
Does the voice simply double in pitch?
Audio uses atempo rather than a basic sample-rate change, but inspect sound quality.
Can audio stay at its old speed?
This form changes video timing and audio tempo by the same factor.
Related tools
You do not need to start over. Continue with the tool that fits your next step.
