MP4 to MP3 | Fast & Free & Secure
Convert MP4 to MP3 online in seconds. No signup. Secure processing; files auto-delete in ~2h. Works on mobile & desktop.
Smart Auto-Detection – ConvertSea
No need to select your file type — we've already detected it.
Just upload your file and choose the format you want to convert it to. Our system automatically recognizes the input format, so you can focus on getting the output you need.
What is MP4?
MP4 (MPEG-4 Part 14) is a flexible multimedia container built on the ISO Base Media File Format. A .mp4 bundles video, audio, subtitles, and metadata into track-based “boxes,” making it ideal for storage and streaming. Common video codecs include H.264/AVC and H.265/HEVC; audio is typically AAC, with ALAC or Dolby Digital (AC-3) sometimes used. MP4 can carry chapters, thumbnails, and subtitle tracks such as 3GPP Timed Text (tx3g), and it supports HDR signaling with HEVC (e.g., HDR10, HLG). Fragmented MP4 (fMP4) powers adaptive streaming like HLS and MPEG-DASH. Because virtually all browsers, phones, TVs, and social platforms play MP4—especially H.264/AAC—it’s the default choice for web video delivery. Editors and players (VLC, QuickTime, Premiere, Resolve) open MP4, and remuxing to MOV or MKV is often lossless when codecs match.
What is MP3?
MP3 (MPEG-1/2 Audio Layer III) is a lossy audio codec designed to shrink music and speech files dramatically while preserving acceptable fidelity. It works by transforming audio into the frequency domain, modeling human perception to discard masked detail, then encoding with Huffman coding and variable-length frames. Typical bitrates range from 96–320 kbps; 128 kbps was common historically, while 192–256 kbps VBR offers better transparency today. MP3 stores stereo, joint-stereo, or mono, supports ID3 tags for artwork and metadata, and plays virtually everywhere—phones, cars, smart speakers, and browsers. Although AAC and Opus are more efficient at the same bitrate, MP3 remains the most compatible choice for distribution and archiving. For best results, rip from lossless sources and avoid repeated re-encoding.
Upload Your File
Upload your file (drag & drop or click). Input type is auto-detected—no need to choose it.
Pick Format & Options
Pick the output format and (if available) adjust options like OCR, quality, bitrate, or resolution.
Convert & Download
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Convert Your Files Instantly – Fast, Secure & Free
Welcome to ConvertSea, the ultimate online tool to convert your files with speed, accuracy, and zero hassle. Whether you're changing image formats, converting videos, editing documents, or extracting audio, our platform delivers instant, high-quality results across hundreds of file types.
No downloads, no registration, and no watermarks — just upload your file, choose the format you need, and download your converted file in seconds.
From PDF to Word, MP3 to WAV, JPG to PNG, or MP4 to MOV, ConvertSea ensures that your content stays clean, secure, and exactly how you want it.