Audio Compressor
Reduce MP3, WAV, M4A and OGG file sizes in your browser. Choose a compression level or set a target size, then compare the original and compressed files.
Leave Target size empty to use the selected compression preset. When a target is set, NeroTool estimates a bitrate from each file's duration and aims below the requested size.
Compress audio files online
Audio Compressor is designed for one job: reducing audio file size. It re-encodes the source using a lossy codec and a practical bitrate so the result is easier to upload, attach or share.
Choose a compression level
Maximum compression
Use the smallest preset when file size matters most, such as a strict upload limit or messaging attachment.
Balanced
Balanced is the best starting point for many recordings and music files because it trades some size for better audio detail.
Higher quality
Higher quality uses a larger bitrate and normally produces a larger file while preserving more detail.
Target a smaller file size
If you know the maximum size you need, enter a target size in megabytes. NeroTool estimates a suitable bitrate from the source duration and applies it to each file. The result can vary because codec overhead and source characteristics affect the final size.
Why WAV and FLAC can shrink dramatically
WAV is often uncompressed PCM, while FLAC is lossless. Re-encoding either to MP3, M4A/AAC or OGG can produce a much smaller lossy file. Keep the original if you may need lossless editing later.
Before and after size
After processing, the tool reports the original size, compressed size, bitrate and percentage saved. Preview the result before downloading or deleting the source.
Batch compression
Select multiple recordings to process them sequentially. Each file gets its own compressed result and download button.
Privacy and local processing
Supported compression is performed locally in your browser with FFmpeg.wasm. Your selected audio is not intentionally uploaded to a NeroTool processing server.
Compress audio for smaller files
Audio compression is useful when files need to fit upload limits, use less storage or download faster. A good result balances size and listening quality instead of applying the strongest compression to every recording.
Choose a practical bitrate
Speech and simple voice recordings can often work well at lower bitrates, while music benefits from retaining more information. If you set a target file size, compare the resulting audio with the original before using it for a final upload or archive.
If you need a different format rather than a smaller file, use Audio Converter. For video sound extraction, see Video to MP3.
Frequently asked questions
How much can I reduce an audio file?
It depends on the source format, duration and chosen bitrate. Uncompressed WAV files can often shrink dramatically when encoded as MP3 or AAC.
Can I target a specific file size?
Yes. Enter a target size per file and the compressor estimates a bitrate from the audio duration. The final size is an estimate, not a guarantee.
Will compression reduce audio quality?
Lossy compression removes some audio information. Higher quality settings generally preserve more detail but create larger files.
Is my audio uploaded?
No. Supported compression runs locally in your browser with FFmpeg.wasm.