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Free Video Speed Changer
0.25× slow-mo to 4× speed-up — pitch-corrected.
Change video speed online in under 30 seconds. Slow it down for cinematic slow-mo (0.25× / 0.5×) or speed it up to fit a tight time-cap (1.5× / 2× / 4×). We pitch-correct the audio automatically so voices stay natural — no chipmunk effect, no muffled bass.
How Video Speed Changer works
- 1
Upload your video
Drop an MP4, MOV, or WebM up to 500 MB. Browser-based — your file never sits on a third-party CDN longer than the render itself.
- 2
Pick a speed
Six presets — 0.25×, 0.5×, 1.5×, 2×, 3×, 4× — or type a custom multiplier. Toggle "preserve audio pitch" on (default) for natural-sounding voices, or off for the classic chipmunk/slowed effect.
- 3
Download
We re-encode with ffmpeg server-side and return an MP4 within seconds. Free, no watermark, no account needed.
Why CinobiLabs
- Pitch-corrected audio — no chipmunk effect
- 0.25× to 4× range, six presets + custom
- Free, no watermark, no signup
- Browser-based — your video never persists on our servers
Frequently asked questions
How much can I speed up or slow down a video?
Range is 0.25× (4× slower) to 4× (4× faster). Beyond 4× the audio becomes unintelligible and frames start dropping noticeably; beyond 0.25× the playback gets jerky on most players. Within those bounds the output is smooth.
Does the audio sound okay after speed change?
Yes — we use ffmpeg's atempo filter which pitch-corrects the audio so voices keep their natural tone. Compare to the iMovie default (which doesn't pitch-correct and makes voices chipmunk-y at high speed).
Will the file size change?
Slowing down a video makes it larger (more frames per second of output); speeding up makes it smaller. The codec stays the same — H.264 in, H.264 out — so quality is preserved.
What's the max file size?
500 MB. For larger videos, use our Video Compressor tool first (also free) — it can shrink a 2 GB phone video to under 200 MB without visible quality loss.
Is this watermark-free?
Completely. No watermark, no logo, no overlay. The output is yours — use it on social, in client projects, anywhere.
Can I do slow-mo on phone videos?
Yes — even videos that were already shot at 60fps or 240fps can be slowed further. We respect the original frame rate and just stretch the playback timing. For genuine super-slow-mo (≥10× slowdown), shoot at 120fps+ on your phone first; otherwise the output gets choppy.
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Ready to try it?
Sign up free — 50 credits on signup, no card required.
Open Free Video Speed Changer →