zerouploads

Video Compressor

Make a video smaller by asking for a quality, not a file size. Nothing is uploaded and there is no watermark.

  • Preview
  • Unlimited
  • No signup
  • Private
  • Works offline

Make a video file smaller

Quality

H.264 in an MP4 plays on everything. VP9 in a WebM is smaller at the same quality and takes noticeably longer to make.

How long the encoder thinks about each frame. Slower spends more time to reach the same quality in fewer bytes.

How the file is written
Commandffmpeg -i input.mp4 -c:v libx264 -crf 23 -preset medium -vf scale=-2:720 -pix_fmt yuv420p -c:a aac -b:a 128k -movflags +faststart video-compressed.mp4
Choose a video to start

How it works

  1. 01

    Add a video

    Drop it or choose it. It plays here first, so you can see what you are working on.

  2. 02

    Pick a quality

    Good suits almost everything. Drop the resolution too if it is going to a phone.

  3. 03

    Save it

    The bar fills and the file downloads. The page shows what it saved.

How a video gets smaller

Two things decide the size: how many pixels each frame holds, and how many bits are spent describing them. Resolution is the first, quality is the second, and dropping either one shrinks the file.

This tool asks for a level of quality and spends whatever it takes to reach it. A still talking head needs very few bits and comes out tiny. A snowstorm needs many and comes out large. The alternative is to fix the bitrate instead. That hits the number you asked for, and lets the picture fall apart on the one clip that needed more.

That is why there is no size promised before you start. The honest answer depends on what is moving in your footage, and you get the real number the moment it finishes.

Input
MP4, MOV, MKV, WebM and AVI. One video at a time.
Output
H.264 in an MP4, or VP9 in a WebM. Four quality levels.
Resolution
Keep the original, or drop to 1080p, 720p, 480p or 360p.
Sound
Re-encode it at 128 kbps, leave it untouched, or remove it.

What to pick, and when

Most phone video is 1080p or 4K, and most places it ends up show it far smaller. 720p is plenty for chat, email and a slide. Keep 1080p if it is going on a television or into an edit.

Good quality is the default for a reason. High is for footage you will edit again. Smaller suits email limits. Smallest softens the picture in a way you will see on detail like grass or hair.

H.264 in an MP4 plays on everything, which is what you want if you are sending it to someone. VP9 in a WebM is smaller at the same quality but takes noticeably longer to make, so it suits a file for your own site.

Effort changes only the time it takes, never the quality you asked for. Slow spends longer finding a cheaper way to say the same thing, so the file comes out smaller for the same picture.

Frequently asked questions

Is my video uploaded?
No. It is read and re-encoded in this tab by your own browser. Nothing is sent, so there is no upload wait and no size cap.
How much smaller will it be?
It depends on what is moving in the footage, so the page does not guess. Phone video at 720p and Good quality often lands near a tenth. The real figure appears when it finishes.
Will it look worse?
A little, and Good quality is chosen so most people cannot see it. High keeps more for editing. Smallest is the one where you will notice, on detail like grass or hair.
Should I pick MP4 or WebM?
MP4 if you are sending it to someone, because H.264 plays everywhere. WebM if it is for your own website and you can wait longer for a smaller file.
Why is it slow?
Re-encoding video is the heaviest thing a browser can be asked to do, and it is all happening on your machine. A shorter clip, a lower resolution or Fast effort all help.
Can I compress several at once?
Not yet. One video at a time, because the whole file is held in memory while it is encoded. A batch would run a laptop out of room.
Browse all video tools