How to use the Compress AVI
- Choose the AVI.
- Pick a compression level or target size.
- Compress.
- Download the MP4.
Why the result is MP4
AVI was designed for old codecs such as DivX and XviD, which need two to three times more data than H.264 for the same quality. To make the file genuinely smaller, the compressor saves it as MP4 with H.264, which also plays on phones and in browsers. If you specifically need an AVI, use MP4 to AVI afterwards.
Good to know
Compression uses H.264 (x264, "veryfast" preset) with either a quality target (CRF) or a calculated bitrate for target sizes. Audio is re-encoded to AAC. The file is never uploaded, so even private videos can be compressed safely.
Supported files
MP4, MOV, MKV, WEBM, AVI, WMV, FLV, M4V, 3GP, 3G2, MPEG, MPG, TS, MTS, M2TS, VOB, OGV, MXF, ASF, DIVX, F4V, SWF, DV, MOD, TOD, WTV, RM and RMVB video, with H.264, HEVC, VP8, VP9, MPEG-4, MPEG-2, WMV, Theora and other codecs. AV1 videos cannot be read in the browser yet. Files up to 1 GB each.
Frequently asked questions
How much smaller will it be?
Old AVI files often shrink by 50–80% at the same visual quality.
How much does the Compress AVI cost?
Nothing. It is free with no registration, no watermark and no limit on how many files you convert.
Are my files safe?
Yes. Files are converted locally in your browser and are never uploaded. When you close the page, nothing is left behind.
Can I use it on my phone?
Yes. Open the page in your phone's browser and choose a file. Phones have less memory than computers, so very large files are better converted on a laptop or desktop.