Glowtrack Studio Video Speed

Video Speed Changer — Slow Motion & Fast Forward

Speed up or slow down a video, free in your browser: 0.25× slow motion up to 4× timelapse, with the voices kept natural or pitched up for fun. Preview it, then download an MP4. Nothing is uploaded.

Drop a video here, or click to chooseMP4, MOV, WebM or MKV ·

Advertisement

How it works

  1. Drop in a videoAny MP4, MOV, WebM or MKV.
  2. Pick a speedFrom 0.25× slow motion to 4× fast forward, and choose what happens to the sound.
  3. DownloadGet an MP4 at the new speed, ready to post.

Speed, frames and sound

Slow motionEach frame is shown for longer. For smooth slow motion, film at 60 fps or more and slow it to 0.5× or 0.25×.
Fast forwardFrames are skipped to keep the result smooth — great for timelapses of drawing, cooking or travel.
Natural voicesThe sound is time-stretched so speech stays at its normal pitch.
Chipmunk modeOr let the pitch follow the speed — high and squeaky when fast, deep and slow when slow.

FAQ

Is my video uploaded?

No. The video is processed inside your browser on your own device and never sent anywhere — so it’s fast to start and safe for private clips.

How do I make a slow-motion video?

Drop it in, choose 0.5× or 0.25×, and press Change speed. Videos filmed at 60 fps or more look smoothest in slow motion.

Can I speed up a video without the chipmunk voice?

Yes — that’s the default. “Keep the pitch” stretches the audio so voices sound normal at any speed.

Can I speed up only part of a video?

This tool changes the selected part. To speed up just the middle, trim that part out here, then join the pieces with the merge tool.

Which browser works best?

Chrome or Edge on a computer are fastest, because they use your graphics card to encode video. Safari works for most files; phones work for shorter clips.

Is it free?

Yes — free, no sign-up and no watermark. The site is supported by the ads on the page.

More free video tools

Trim videoCut the start and end off, or cut a section out. Merge videosJoin clips into one video. Add music to videoPut a song under your clip. Rotate videoTurn or flip a sideways video.