What is the easiest way to reduce a video file size?

Use a browser compressor for one file when you want a quick preview and no upload. Choose a target size, then keep the original in case the result is too soft.

Is MP4 smaller than WebM?

Neither is always smaller. The codec, bitrate, duration and image content matter more than the container name. WebM can be efficient for the web. MP4 is usually easier to share across phones and editing apps.

How do I compress a video to 8 MB?

Set a target bitrate from the duration and leave a little room for audio. The video compressor does that calculation in the browser, then reports the final size after encoding.

How to compress and convert a video

Pick the output you actually need. A target size, a compatible format and a suitable width matter more than a slider labelled “high quality”.

Free toolVideo Compressor / ConverterMake a video smaller or convert it to MP4, WebM, MOV or MKV. Aim for 8 MB, 10 MB or 25 MB, then export locally with no upload.Compress a video

The short answer

For one file, open the video compressor / converter, choose MP4 or WebM and set a goal. The browser tool keeps the video on your device. For a format change with compatible tracks, choose conversion without recompression. For repeatable batches or unusual codecs, use a desktop app or ffmpeg.

Method	Best for	Tradeoff
Browser	One file, no install, no upload	Format and codec support vary by browser
Desktop app	Several clips, a timeline or a project file	Install and configure the app
ffmpeg	Scripts, batches and exact codec settings	Command line and codec knowledge

Choose a size before you choose quality

If a form says “under 25 MB”, that is the requirement. A 1080p video with a low frame rate may fit at a higher quality than a fast 4K clip. Duration is the other fixed input: twice the duration needs about half the bitrate to hit the same file size.

Leave space for audio. A simple estimate is target bytes × 8 ÷ duration, then reserve roughly ten percent for audio and container overhead. The browser tool uses the same idea and tells you the actual result after encoding.

MP4 or WebM?

Use MP4 when the file is going to a phone, slide deck, messaging app or broad audience. H.264 video with AAC audio is widely supported.

Use WebM for a website or a workflow that already supports it. VP9 and Opus can give a small result, but some editing apps and older devices will not open it.

Convert without recompression

Changing the container can leave the encoded video and audio untouched. Choose Convert without recompression in the browser tool. It copies recognised video and audio tracks and stops if the chosen format cannot hold one. Embedded subtitles are not copied. The file may grow or shrink because container overhead changes. A new extension does not make an unsupported codec play on every device.

When a smaller width beats a lower bitrate

A 4K source displayed at 854 pixels wide contains far more detail than the viewer can see. Capping the output width reduces the number of pixels in every frame. It often saves more bytes while looking cleaner than forcing a 4K frame through a very low bitrate.

Command line example

For a repeatable MP4 export with ffmpeg, set a video bitrate and copy the audio:

ffmpeg -i input.mov -c:v libx264 -b:v 1800k -c:a aac -b:a 128k output.mp4

To change the width while preserving the aspect ratio, add -vf scale=1280:-2. Test one representative file first. A number that works for a talking head may fail on a fast game recording.

Keep the original

Compression is a new generation. It cannot restore detail that a previous export removed. Keep the original until you have checked the new file on the device and service that will receive it.