Speed Forge
Free online video speed changer. Speed up or slow down any clip in your browser, no watermark.
Speed Forge is a free online video speed changer. Take any video, change its playback speed, and download the re-rendered clip. 0.25× slow-mo to 8× hyperlapse in nine preset stops. Audio comes along by default. Toggle it off if you want silence or plan to lay a clean track over the top.
Most "speed up video" pages on the open web slap a watermark on the output, cap your file size, or send your footage through their server for the privilege. None of that is necessary anymore. Speed Forge runs the whole job in your browser.
- 01Drop a video file (mp4, webm, mov), or click to pick one.
- 02Pick a speed. 0.25× is quarter speed (slow-mo), 1× is unchanged, 8× is hyperlapse.
- 03Decide whether to keep the audio. At slow speeds audio drops in pitch, at fast speeds it rises.
- 04Click Render. Wall-clock time is roughly the OUTPUT clip length: 30s at 0.25× takes around 2 minutes.
- 05Download. Files save as <source>-Nx.webm.
- Audio pitch shifts with playback speed. There's no clean pitch-preserving re-encode in the browser yet. Mute the audio toggle if that's a problem.
- WebM output uses your browser's native MediaRecorder. Codec is VP9 on Chrome and Edge, VP8 on Firefox. Quality is consistent across both.
- Slow renders take longer than the source: a 30-second clip at 0.25× renders in about two minutes. Fast renders finish in a fraction of source length.
- Nothing leaves your machine. No upload, no server, no account.
Is Speed Forge free, and does it add a watermark?
Yes, it’s free. No account, no upload, no watermark on the output, ever.
Can it slow down video too, not just speed it up?
Yes. The slow side goes to 0.25× (quarter speed) for slow-motion clips. The fast side goes to 8× for hyperlapse.
What file formats does it accept and export?
Input: mp4, webm, mov, m4v, and mkv. Output: pick MP4 or WebM in the Format toggle. MP4 (H.264) works on Safari, Chrome 122+, Edge, and other modern Chromium browsers. WebM (VP9 / VP8) works everywhere, including Firefox.
Why is the audio higher or lower pitched?
Browsers don’t yet expose a clean pitch-preserving re-encode. When you change playback speed the pitch shifts. If that’s a problem, toggle the audio off and lay a clean track in afterward.
How long can my video be?
There’s no hard cap. The practical limit is your browser’s memory. A few minutes is comfortable on most machines.
Does it work on a phone?
Yes. Mobile Chrome and Safari can both render, though long renders may be slower than on a laptop.
Where does my video go?
Nowhere. The clip stays in your browser tab. There is no upload and no server processing.
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