Media Converter
Free online audio and video format conversion and trimming tool: convert audio between MP3, WAV, M4A, AAC, FLAC, OGG; change video containers (e.g., mkv→mp4) or re-encode, and trim by time. All processing happens locally in your browser—no file uploads, full privacy, completely free.
FAQ
No. Conversion and trimming are done entirely in your browser using WebAssembly, with no file uploaded to any server—this can be verified in your browser's network panel.
Container-only conversion (e.g., mkv→mp4) doesn't re-compress the video, completing instantly with no loss, but requires compatible source encoding; re-encoding performs actual transcoding, is more universal but slower in the browser, suitable for short clips.
Video encoding is computationally intensive, and browser single-threaded processing is slow. To prevent long delays, re-encoding is limited to ≤5 minutes duration and ≤500MB file size; you can first trim the clip before converting.
In container-only/copy-stream mode, trimming aligns to the nearest keyframe, which may cause slight offset at start; for frame-accurate trimming, use the "re-encoding" mode.
Audio: MP3, WAV, M4A (AAC), AAC, FLAC, OGG; Video containers: MP4, MKV, MOV, WebM. Converting to WebM requires re-encoding since it uses different codecs than MP4.