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 audio files from MP3 to the high-efficiency OPUS format. This tool is ideal for developers and streaming services looking to optimize audio delivery.
MP3 is a legacy lossy audio container widely supported by hardware players, while OPUS is a modern, versatile lossy container designed for low-latency and high-quality streaming. During conversion, the audio stream is decoded from the MP3 codec and re-encoded into the OPUS codec. Because both formats utilize lossy compression algorithms, this process involves generational loss, meaning the original audio data is transformed and re-compressed, which can lead to slight fidelity degradation.
Since both MP3 and OPUS use lossy compression, re-encoding will inevitably cause a minor reduction in audio fidelity compared to the source file.
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.
Music, podcasts, voice recordings, and sound effects.
Common extensions: MP3, WAV, FLAC, OGG, AAC, M4A, OPUS
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
Clips, streams, screen recordings, and movies.
Common extensions: MP4, WebM, MOV, MKV, AVI, MPEG
