Will the voice sound weird?

No, pitch is preserved; only the tempo changes.

Why is my slow motion choppy?

The source has too few frames. Shoot at a higher frame rate for smoother results.

Can I speed up only audio?

Use the audio speed tool for audio files.

Does the file get smaller when sped up?

Usually yes, because it is shorter.

Can I change speed for just part of the clip?

Split or trim the part first, change its speed, then merge the pieces back.

Is there a maximum length?

No fixed limit; long clips just take longer and need more memory.

Can I make a timelapse from a long recording?

Yes. Use 4×, then run the result through again for 16× or 64×; each pass also shrinks the file.

Does speed change work on phones?

Yes. Short clips process comfortably in mobile Chrome and Safari.

100% free · runs in your browser · no upload · no signup

Change Video Speed Online

Drop a file here

Click to browse, or paste a file from the clipboard.

Choose file

This tool makes a video play faster or slower, from 0.25× slow motion to 4× timelapse, and keeps voices at their natural pitch. It runs in your browser and writes an MP4.

How to use video speed

Drop the video onto the box above.
Pick a speed: under 1× slows down, over 1× speeds up.
Press Change speed and wait for the progress bar.
Preview and download the MP4.

How video speed works

Video timestamps are rescaled so frames play faster or slower, and audio goes through FFmpeg's atempo filter, which stretches time without the chipmunk or slow-drawl effect of simply changing the sample rate.

atempo only accepts 0.5 to 2.0 per pass, so speeds outside that range are chained (4× = 2× then 2×) to stay clean.

Clips with no audio track are handled: the tool retries as a silent speed change.

Under the hood the tool rewrites each frame's presentation timestamp with the setpts filter, so a 2× clip shows the same frames in half the time and a 0.5× clip holds each frame twice as long. Nothing is interpolated, which keeps the result faithful to the source.

Everything runs on your device. See also Audio speed.

At a glance

Property	Videozify
Range	0.25× to 4×
Audio	Pitch-preserved (atempo)
Output	H.264 MP4 + AAC
Processing	In your browser

This tool makes a video play faster or slower, from 0.25× slow motion to 4× timelapse, and keeps voices at their natural pitch.

Settings explained

Slow motion from a normal 30 fps clip will look steppy because no new frames are invented. For smooth slow-mo, film at 60 or 120 fps and slow that down.

For tutorials, 1.25× or 1.5× tightens pacing without making speech hard to follow.

Speed settings for common jobs

Lectures and screen recordings: 1.25× to 1.5× keeps speech understandable while cutting viewing time by a fifth to a third. Pitch correction means voices still sound natural.

Timelapse of a slow process such as cooking, drawing or a sunset: 2× to 4×. For an even faster effect, run the result through the tool twice; 4× twice is 16×.

Dramatic slow motion: 0.5× from footage shot at 60 fps gives smooth 30 fps playback. From normal 30 fps footage the motion will stutter because each frame is shown twice.

The output keeps the original resolution. Speeding up a clip also makes the file smaller in proportion, which can help when a platform has a length limit.

Frequently asked questions

Will the voice sound weird?: No, pitch is preserved; only the tempo changes.
Why is my slow motion choppy?: The source has too few frames. Shoot at a higher frame rate for smoother results.
Can I speed up only audio?: Use the audio speed tool for audio files.
Does the file get smaller when sped up?: Usually yes, because it is shorter.
Is it uploaded?: No, processing is local.
Is it free?: Yes, no watermark.
Can I change speed for just part of the clip?: Split or trim the part first, change its speed, then merge the pieces back.
Is there a maximum length?: No fixed limit; long clips just take longer and need more memory.
Can I make a timelapse from a long recording?: Yes. Use 4×, then run the result through again for 16× or 64×; each pass also shrinks the file.
Does speed change work on phones?: Yes. Short clips process comfortably in mobile Chrome and Safari.