Compress Audio Files Online for Free
Make an audio file smaller in your browser. Works with MP3, WAV, M4A, FLAC, OGG and more. No upload, no signup, no watermark.
Click or drag & drop to upload your file
Why compress audio with Whisper Web?
Stays on your device
Compression runs in your browser. Your recording is not uploaded to a server, which matters for interviews, voice notes and anything private.
Free, no signup
No account, no watermark and no daily limit. Open the page, drop a file and download the result.
See the size first
Pick a level and the page shows the estimated size for your file before you start.
Common audio formats
Works with MP3, WAV, M4A, AAC, FLAC, OGG and more, and gives you a file that plays everywhere.
How to compress an audio file
- 01
Choose your audio
Drop a file onto the box or click Select a file. Nothing leaves your device.
- 02
Pick a compression level
Smallest file, Best balance or Best quality. Each one shows the size you can expect for your file.
- 03
Compress and download
Click Compress, wait for the progress bar to finish, and download your smaller MP3 or M4A file.
Free online audio compressor
What an audio compressor does
An audio compressor lowers the bitrate of a recording so the file takes less space and uploads faster. This one runs in your browser: choose a file, pick how small it should get, and download the result.
Why shrink an audio file?
Recordings add up quickly. An hour of uncompressed stereo audio is more than 600 MB, and even a long MP3 can be too big for an email, a messaging app or an upload form. A smaller file is faster to send and cheaper to store, and for speech the difference in sound is often small.
When a smaller audio file helps
Sharing a podcast episode or a voice note, sending an interview to a colleague, uploading a recording to a service with a size cap, or clearing space on a phone. If you plan to transcribe the recording afterwards, a smaller file uploads faster and speech stays clear at the Best balance level.
How the compression works
The tool re-encodes the audio at a lower bitrate. It reads the length and size of your file, lowers the bitrate by the share the level calls for, and never goes above a ceiling for that level, so a lossless file ends up far smaller while a file that is already compressed changes less. Everything runs in your browser.
Formats it handles
MP3, WAV, M4A, AAC, FLAC, OGG, Opus, WMA, AIFF and most other common audio files. The result is an MP3 file, except for M4A and AAC files, which stay M4A.
What each level does
Smallest file caps the bitrate at 64 kbps, which is clear for speech and noticeably limited for music. Best balance caps it at 112 kbps. Best quality caps it at 192 kbps. For a file that is already compressed, each level lowers the bitrate by about 70%, 50% or 30%, down to a floor of 40 kbps, and the page shows the estimated size for your file before you start.
Frequently asked questions
How do I reduce an audio file's size?
Drop your file onto the box, choose a compression level, click Compress and download the result. The tool lowers the file's bitrate. Everything happens in your browser.
How much smaller can an audio file get?
A lossless file such as WAV or FLAC usually shrinks by well over half, and often by 90% or more. An MP3 or M4A shrinks by about 30%, 50% or 70% depending on the level, and a file that is already at a low bitrate shrinks less. The page shows the estimate for your file before you start.
Does compressing audio reduce its quality?
Yes. The output is lossy, so some detail is removed. Speech and podcasts hold up well at Best balance. For music, Best quality is the safer choice. Keep your original file and compress a copy.
Which audio formats can I compress?
You can compress MP3, WAV, M4A, AAC, FLAC, OGG, Opus, WMA and AIFF files, among others. The result is an MP3 file, except for M4A and AAC files, which stay M4A. Both play on every phone and computer.
Is this the same as audio dynamic range compression?
No. This tool makes the file smaller by lowering its bitrate. It does not change how loud or quiet a recording is. If you are looking for a compressor effect that evens out volume, you need an audio editor or a plug-in.
Is there a file size limit?
Files up to 2 GB are accepted. Very large files can take a while and need a lot of memory, so close other tabs first. There is no limit on how many files you compress.
Can I compress audio without losing quality?
Not with this tool. Any method that makes a file much smaller removes some information. Best quality is the closest it gets, at a bitrate of up to 192 kbps.
Can I compress audio on my phone?
It runs in the browser, so it can work on a phone, but we have mainly tested desktop browsers. Very long recordings are more reliable on a computer.
Is my audio uploaded?
No. The file is read and compressed inside your browser, and the result is created on your device. Only the page and the compression code are downloaded.