Compress MP4 video with useful quality presets
High quality, Balanced, and Small file presets set a sensible CRF, resolution, and audio bitrate.
Measured local H.264 compression
Free Online Video Compressor to Reduce MP4 File Size Without Uploading
Select a quality preset or tune resolution and CRF, then compare the real input size, output size, and compression ratio.
No upload No signup No watermark
Open the tool Compressed video preview
Choose a local video to estimate and reduce its file size.
Set custom video resolution and H.264 CRF
Keep source resolution or cap output at 1080p, 720p, or 480p while adjusting CRF from 18 to 35.
Compare original and compressed video size
The tool reports actual bytes and ratio after encoding instead of promising an estimated reduction.
How to compress an MP4 video online without losing too much quality
Start with the Balanced preset, preview the result, and compare its measured file size. If details look soft, lower CRF; if the file remains too large, raise CRF or cap resolution at 720p.
Compression effectiveness depends on source codec, motion, noise, resolution, and bitrate. There is no fixed percentage that applies to every video.
Best CRF and resolution settings for smaller browser video
CRF controls perceptual quality for H.264: 18 is visually close to the source but larger, while 28 to 32 trades more detail for size. Downscaling often saves more space than aggressive CRF alone.
For large or long files, native FFmpeg with hardware acceleration is faster and less constrained by browser memory.
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Common questions
Video Compressor frequently asked questions
Straight answers about browser support, privacy, source access, and output behavior.
What CRF should I use to compress an MP4 video?
CRF 23 to 28 is a practical range. Lower values keep more detail; higher values usually create smaller files.
Can the compressed file become larger?
Yes. A small or already efficient source may grow when re-encoded. The tool reports the real before-and-after size so you can adjust settings.
Does video compression run on a server?
No. H.264/AAC encoding runs locally with FFmpeg.wasm and can be CPU intensive on long videos.