Is this video speed changer free?

Yes, completely free. No account, no subscription, and no watermark on the output. Just open the page and start converting.

Is my video uploaded to a server?

No. All processing runs locally in your browser via ffmpeg.wasm. Your video never leaves your device and is never seen by any server or third party.

Does changing the speed affect the audio pitch?

No. The tool applies pitch correction automatically so voices and music stay at their natural pitch regardless of the playback speed you choose.

What speed range is supported?

You can set any speed from 0.25x (quarter speed, extreme slow motion) up to 4x (four times faster). Common choices are 0.5x for slow motion, 1.5x or 2x for faster viewing, and 4x for rapid review.

Does it work on mobile devices?

Yes. The tool works on modern mobile browsers (Chrome for Android, Safari on iOS 16+) that support WebAssembly. Processing time depends on your device speed and video file size — shorter clips convert fastest.

⏩ Change Video Speed — Slow Motion & Fast Forward, Free & Private

Speed up or slow down any video instantly — 100% free, no upload required, and your file never leaves your device. Choose a speed from 0.25x (slow motion) to 4x (fast forward), and the tool re-encodes the video right in your browser using ffmpeg.wasm.

Choose a video

Speed

Private by design. This tool runs entirely in your browser — nothing you enter is uploaded or stored, and it works offline.

About

This tool uses ffmpeg.wasm — a WebAssembly port of the industry-standard FFmpeg library — to re-encode your video at a new playback speed entirely inside your browser. Because all processing is client-side, your video file is never transmitted to any server, never stored in the cloud, and never seen by anyone but you. The audio pitch is automatically corrected so speech and music stay natural even at 2x or 0.5x speed. Supported input formats include MP4, MOV, WebM, AVI, and MKV; output is always MP4 for maximum compatibility. The tool works on desktop and mobile browsers that support WebAssembly, and once the ffmpeg.wasm engine is loaded it continues to work fully offline.

How to use

Click 'Choose Video' and select a video file from your device (MP4, MOV, WebM, AVI, or MKV).
Set your desired playback speed using the slider or input — from 0.25x (slow motion) to 4x (fast forward).
Click 'Change Speed'. ffmpeg.wasm processes the video locally in your browser — no upload occurs.
Preview the result in the built-in player, then click 'Download' to save the new MP4 to your device.

FAQ

Is this video speed changer free?: Yes, completely free. No account, no subscription, and no watermark on the output. Just open the page and start converting.
Is my video uploaded to a server?: No. All processing runs locally in your browser via ffmpeg.wasm. Your video never leaves your device and is never seen by any server or third party.
Does changing the speed affect the audio pitch?: No. The tool applies pitch correction automatically so voices and music stay at their natural pitch regardless of the playback speed you choose.
What speed range is supported?: You can set any speed from 0.25x (quarter speed, extreme slow motion) up to 4x (four times faster). Common choices are 0.5x for slow motion, 1.5x or 2x for faster viewing, and 4x for rapid review.
Does it work on mobile devices?: Yes. The tool works on modern mobile browsers (Chrome for Android, Safari on iOS 16+) that support WebAssembly. Processing time depends on your device speed and video file size — shorter clips convert fastest.