Any file up to 500 MB. Drop several files and they come back as one ZIP. Many image, audio and video conversions run in your browser; anything else is uploaded and removed within the hour.
Convert your MKV video files to AAC audio format instantly. This tool is perfect for users who need to extract the soundtrack from a movie or video clip to save it as a standalone audio file.
MKV is a versatile multimedia container designed to hold video, audio, and subtitles, while AAC is a dedicated audio format optimized for high-quality sound compression. When you perform an MKV to AAC conversion, the system strips away the video stream and re-encodes the embedded audio track into the AAC codec, effectively transforming a video file into a lightweight audio file.
Since both formats utilize lossy compression, the conversion process involves re-encoding the audio track, which may lead to a minor generational loss in fidelity.
We built this project so anyone can convert files without paywalls, accounts, or hidden limits. Here is what that promise means in practice.
Every converter on ConvertX is free to use: no trials, no premium tiers, and no credit packs. We will never put core conversion features behind a subscription. Whether you convert one photo or a hundred files a week, the price stays zero.
Many image, audio, and video conversions run entirely in your browser. Your files never leave your device for those jobs. When server processing is required for documents or specialized formats, uploads are handled securely and removed automatically — typically within one hour.
A quick guide to strengths and trade-offs of popular formats — so you pick the right one before converting.
Clips, streams, screen recordings, and movies.
Common extensions: MP4, WebM, MOV, MKV, AVI, MPEG
Raster and vector graphics for web, print, and photography.
Common extensions: PNG, JPG, WebP, AVIF, GIF, SVG, HEIC, TIFF
Office files, PDFs, ebooks, and plain text.
Common extensions: PDF, DOCX, XLSX, PPTX, ODT, EPUB, TXT
Music, podcasts, voice recordings, and sound effects.
Common extensions: MP3, WAV, FLAC, OGG, AAC, M4A, OPUS
