Free Audio Compressor

An audio compressor reduces the file size of audio recordings by removing inaudible or redundant data. Unlike dynamic range compression used in music production, file compression focuses on encoding efficiency — representing the same sound with fewer bytes. This is essential for sharing music, distributing podcasts, optimizing website audio, and saving storage space on your devices.

Our tool uses FFmpeg compiled to WebAssembly, running entirely in your browser. This means your audio files are never uploaded to a server. You get professional-grade audio processing with complete privacy, zero wait times, and no file size limits.

Audio Formats Explained

MP3 remains the most universally compatible audio format. Developed in the early 1990s, it uses psychoacoustic models to remove sounds that human ears cannot perceive. At 128 kbps, MP3 is considered “near-CD quality” by most listeners. At 320 kbps, even trained audiophiles struggle to distinguish it from the original in blind tests. MP3 files are typically 1 MB per minute at 128 kbps.

WAV (Waveform Audio File Format) stores raw, uncompressed audio data. A single minute of stereo audio at CD quality (44.1 kHz, 16-bit) takes approximately 10 MB. WAV files are roughly 10 times larger than equivalent MP3 files but preserve every sample perfectly. They are the standard for music production, sound design, and any workflow where editing quality matters.

AAC (Advanced Audio Coding) is the successor to MP3. It delivers better sound quality at the same bitrate, which is why Apple chose it as the default format for iTunes and iPhone. At 128 kbps, AAC sounds noticeably better than MP3 at the same bitrate. Spotify uses AAC at 256 kbps for its premium tier on some devices.

OGG Vorbis is an open-source, royalty-free format that competes with MP3 and AAC on quality. It is widely used in gaming, open-source software, and streaming platforms like Spotify (which uses OGG Vorbis at 320 kbps for its premium desktop tier). OGG files are generally smaller than MP3 at equivalent quality.

FLAC (Free Lossless Audio Codec) compresses audio without any loss of quality. FLAC files are about 50-60% the size of the equivalent WAV file while being bit-for-bit identical when decoded. FLAC is the preferred format for archiving music collections and high-fidelity listening.

Lossy vs Lossless Audio

Lossy formats (MP3, AAC, OGG) permanently discard audio data that psychoacoustic models determine is inaudible or less important. The higher the bitrate, the more data is preserved and the better the quality. Once audio is compressed with a lossy codec, the removed data cannot be recovered — this is why you should always keep your original lossless files as masters.

Lossless formats (WAV, FLAC, ALAC) preserve every sample of the original recording. WAV is uncompressed, while FLAC and ALAC use mathematical compression (similar to ZIP) to reduce file size without losing any audio data. Lossless files can be perfectly reconstructed to the original PCM data.

Choosing the Right Bitrate

Spotify streams at 320 kbps on its Premium tier, while Apple Music uses AAC at 256 kbps. YouTube Music streams at up to 256 kbps AAC. For most people, 192 kbps is the sweet spot where quality is indistinguishable from the original while keeping file sizes manageable. A 4-minute song at 192 kbps is approximately 5.6 MB.