Compress Video Online (Free, No Upload)

Shrink your video files without uploading anything. This tool runs right in your browser, so your files stay on your device the entire time. Pick between H.264 (works everywhere) or H.265 (smaller files), adjust the quality, and download your compressed video. Completely free, no account required.

Try it in your browser

Loading FFmpeg engine... (~31 MB)

How to compress video online online

1Drop your video file into the tool above, or click to browse your files.
2Pick a compression preset or adjust the quality slider to your liking.
3Hit compress and download your smaller file. Works on any device: Chrome, Firefox, Safari, Edge.

About MP4 format

Video compression reduces file size by removing redundant data between frames. Modern codecs like H.264 and H.265 are very good at this: they look at what changes from one frame to the next and only store the differences.

H.264 is the most widely supported codec. Pretty much every device, browser, and social media platform can play it. H.265 (also called HEVC) produces smaller files at the same quality, but not every device supports it yet.

The quality slider in this tool controls a setting called CRF (Constant Rate Factor). Lower numbers mean higher quality and bigger files. Higher numbers mean more compression and smaller files. A CRF of 23 is a good starting point for most videos. For stuff you want to keep looking sharp, try 18 to 20. For quick shares where size matters more, 28 to 32 works well.

Use the API

curl -X POST https://renderio.dev/api/v1/run-ffmpeg-command \
  -H "X-API-KEY: ffsk_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
  "ffmpeg_command": "-i {{in_video}} -c:v libx264 -crf 28 -preset fast -c:a aac -b:a 128k {{out_video}}",
  "input_files": {
    "in_video": "https://example.com/input.mp4"
  },
  "output_files": {
    "out_video": "output.mp4"
  }
}'

Need an API key? Get your free API key to start processing files programmatically.

Common Variations

Maximum compression with H.265

-i input.mp4 -c:v libx265 -crf 32 -preset fast -c:a aac -b:a 96k output.mp4

Balanced quality (CRF 23)

-i input.mp4 -c:v libx264 -crf 23 -preset medium -c:a aac -b:a 128k output.mp4

Target file size (2-pass, ~10MB for 1min)

-i input.mp4 -c:v libx264 -b:v 1200k -pass 1 -an -f null /dev/null && ffmpeg -i input.mp4 -c:v libx264 -b:v 1200k -pass 2 -c:a aac -b:a 128k output.mp4

Downscale to 720p and compress

-i input.mp4 -vf scale=-2:720 -c:v libx264 -crf 28 -c:a aac -b:a 96k output.mp4

Frequently Asked Questions

Is this video compressor really free?+

Yes, completely free. No account, no signup, no hidden fees. Use it as many times as you want.

Are my files safe? Do you upload my video?+

Your files never leave your device. The compression runs locally in your browser. Nothing gets uploaded to any server, and we don't store or track anything.

What's the maximum file size?+

There's no hard limit since processing happens on your device. Larger files will take longer depending on your hardware, but there's no server-side cap.

Does this work on iPhone and Android?+

Yes. It works on any device with a modern browser: Chrome, Firefox, Safari, or Edge. Desktop and mobile both work fine.

Can I compress video without losing quality?+

You can get very close. Lower CRF values (like 18 to 23) keep quality high while still cutting file size by 40-60%. Most people can't tell the difference.

What video formats are supported?+

You can drop in MP4, MOV, AVI, MKV, WebM, and more. The output is MP4 with H.264 encoding for maximum compatibility across devices and platforms.

How much smaller will my video get?+

It depends on the source. A typical phone video or screen recording shrinks by 50-90%. Files that are already heavily compressed will see smaller reductions.

Can I compress a video for email or Discord?+

Yes. The compressor is great for getting videos under email attachment limits (usually 25MB) or Discord's file size cap. Just adjust the quality slider until the estimated size fits.

Privacy

Your video files never leave your device. Everything runs locally in your browser. No data is uploaded to any server, nothing is stored, and nothing is tracked.

Related Operations

Need to process at scale?

Automate this with the RenderIO FFmpeg API. Process thousands of files programmatically or through no-code video automation.

Get your API key