How to compress audio files
Add audio files, choose an Output format and Bitrate, then click Compress. The page creates MP3, AAC (M4A), OGG Vorbis, or WAV output in the browser. Target file size uses each file's duration to calculate a bitrate.
- Drop audio files here, or click browse files to select them.
- Choose an Output format and a Bitrate, or turn on Target file size and enter Target size in MB or KB.
- Review the estimate, then click Compress.
- Watch each file's Status as the files are processed in sequence.
- Preview or download completed files, or click Download all as ZIP.
Compress MP3, AAC, OGG, or WAV
The Output format menu has MP3, AAC (M4A), OGG Vorbis, and WAV. Bitrate choices are 96, 128, 192, 256, and 320 kbps. With Target file size off, the selected Bitrate sets the encoded output and changes the estimate.
WAV output is uncompressed. When you choose WAV, the page disables Bitrate and Target file size.
Input: recording.wav
Output format: MP3 - most compatible
Bitrate: 192 kbps - balanced
Output: recording-compressed.mp3Reduce audio file size with Target file size
Turn on Target file size, enter a positive number in Target size, and choose MB or KB. For a file with a readable duration, the page calculates a bitrate and keeps it between 32 and 320 kbps. If the requested size would require a bitrate outside that range, the page may not reach it.
The estimate uses the active bitrate and file durations. If one or more durations cannot be read, the estimate says that duration information is unavailable.
What happens when audio compression finishes
Completed rows show Original, Compressed, Savings, and Status. A completed row has controls for Preview and Download. Download all as ZIP puts the completed outputs into one ZIP made in the browser.
The page processes files one at a time. The picker accepts audio MIME types and names ending in MP3, M4A, AAC, OGG, OGA, WAV, FLAC, OPUS, WMA, AIF, AIFF, or WEBM. A matching name does not guarantee that FFmpeg can decode the file.
Use one file, a batch, or Preview
For one file, choose an Output format and Bitrate, then use that row's Download control after processing finishes.
For several files, add them together and watch each Status as the page processes them in sequence. Download all as ZIP collects the completed outputs.
To compare a result, use Preview in a completed row. The page shows the original audio beside the compressed audio.
When to use Audio Compress Tools
Use Audio Compress Tools when the job is to reduce the size of audio files or change their encoded output. This page handles audio format conversion as part of compression.
Audio stays in the browser while it is processed. When needed, the page downloads the FFmpeg encoder files from unpkg. Source files and completed output blobs stay in browser memory until you remove them or unload the page.
Frequently asked questions
How do I compress audio files to a target size?
Turn on Target file size, enter a positive value in Target size, choose MB or KB, and click Compress. With a readable duration, the page calculates a bitrate between 32 and 320 kbps, so a requested size that needs a bitrate outside that range may not be reached.
Can I compress MP3 files with this page?
Yes, add the MP3, choose MP3 or another available Output format, select a Bitrate, and click Compress. The completed row shows the new size and savings when processing succeeds.
What does WAV compression do?
WAV output is uncompressed, and selecting WAV disables Bitrate and Target file size. The page encodes the result as WAV rather than applying a lossy bitrate.
Why did audio compression fail?
Compression can fail when FFmpeg cannot decode the selected audio or when the encoder does not load. Passing the file picker's MIME or extension check does not confirm that the audio can be decoded.
How accurate is target file size mode?
With a positive target and readable duration, the page calculates bitrate from file duration and constrains it to 32-320 kbps. A requested target that needs a bitrate outside that range may not be achievable, so the estimate is approximate.