A 5-minute WAV recording is about 50 MB; the same audio as a 96 kbps MP3 is 3.5 MB and sounds nearly identical for speech and casual listening. Drop WAV, M4A, FLAC, OGG or MP3 files and get compressed MP3s back in seconds. Decoding and encoding run on your device, faster than real time.
What is Compress Audio?
Our compress audio tool shrinks WAV, MP3, M4A, AAC, OGG, FLAC, OPUS and WEBM audio by converting it to a lower-bitrate MP3 in your browser. You pick the bitrate, from 192 kbps for music down to 32 kbps for voice, and can switch to mono to halve the data for speech.
Uncompressed recordings are huge: five minutes of WAV is around 50 MB, too big for most email and messaging limits. The same audio as a 96 kbps MP3 is about 3.5 MB and sounds nearly identical for speech and casual listening. Drop several files and download them together as a ZIP.
How to compress audio
- Drop audio files.
- Pick a bitrate: 96 kbps for general use, 64 kbps mono for voice.
- Download the MP3s or a ZIP.
How Compress Audio works
MP3 is a perceptual codec. It splits sound into frequency bands and uses a model of human hearing to decide what you will not notice, such as quiet sounds masked by louder ones at a similar pitch. Those details are stored coarsely or dropped, which is how a 1,411 kbps CD-quality stream can shrink to 128 kbps and still sound like the original.
Bitrate sets the budget. At 128–192 kbps music keeps its sparkle; at 64 kbps speech is still clear, especially in mono, because a voice does not need the full stereo picture or the very highest frequencies. For low bitrates the sample rate is lowered too (to 32 kHz or 22 kHz), which focuses bits where voices live.
Here your browser first decodes the file to raw audio, then the LAME MP3 encoder, compiled to run in JavaScript, encodes it on your device. This is much faster than real time: a long podcast compresses in seconds, not minutes.
Key features of Compress Audio
Free batch MP3 compression
Compress a batch of audio files in one run, with no watermark and no length limit. Drop a whole folder of recordings and download every compressed MP3 together in one ZIP file.
Five exact bitrates
Choose 192, 128, 96, 64 or 32 kbps, and the MP3 is encoded at exactly that bitrate, so file size is predictable: about 0.7 MB per minute at 96 kbps and under 0.5 MB per minute at 64 kbps.
Faster than real time
Unlike video compression, audio does not need to play through. Decoding and MP3 encoding run flat out on your device, so a one-hour lecture is usually done in well under a minute on a laptop.
Works with phone recordings
Voice memos (M4A) from iPhone and recordings from Android work in Chrome, Edge, Safari and Firefox on mobile and desktop. MP3 output plays on every device and in every chat app.
Plain, accessible settings
There are just two labelled settings, a bitrate menu and a mono switch, both keyboard operable. Progress is announced to screen readers, and each result shows its bitrate, channels and duration as text.
Recordings stay private
Interviews, therapy notes, meeting recordings and unreleased music are decoded and encoded in your browser and never leave your device. You can confirm in the network tab that no audio leaves your device.
What makes EZ Compress's Compress Audio different
Mono switch for voice
Most audio compressors keep stereo regardless. For interviews, lectures and podcasts, switching to mono halves the data with no loss of clarity, and at 64 kbps the sample rate is tuned for speech.
Many input formats, one output
WAV, FLAC, M4A, AAC, OGG, OPUS, WEBM and MP3 all go in, and you get standard MP3 out, which plays everywhere. There is no need to find a separate converter for each format.
No server, no queue
Sending a 500 MB WAV to a website can take longer than compressing it. Here the audio never leaves your device, and conversion starts as soon as you drop the file, with no waiting list.
Why use Compress Audio?
Use it whenever you need to reduce audio file size because a recording is too big to send or store. Email services cap attachments around 20–25 MB, messaging apps have their own limits, and podcast hosts, learning platforms and websites load faster with lighter files. Compress WAV recordings straight from a recorder or DAW to MP3 and they shrink to a fraction of the size.
It also helps to compress MP3 files and reduce MP3 size when they were saved at a needlessly high bitrate. Re-encoding a 320 kbps MP3 at 128 kbps cuts it by 60% and most listeners will not hear the difference. As an audio compressor for voice, 64 kbps mono is the sweet spot for podcasts, lectures and voice notes.
Who can use Compress Audio?
Podcasters
Turn large WAV exports into 64–96 kbps MP3s for review copies, guest previews or hosts with upload limits, keeping voices clear in mono.
Students
Shrink recorded lectures and seminars to a fraction of their size so a whole term fits on your phone without filling the storage.
Journalists and researchers
Compress interview recordings before sharing them with editors or transcription services, without sending sensitive source audio to yet another website first.
Musicians
Send demo mixes as 128–192 kbps MP3s that bandmates and producers can stream on any phone, while keeping the full WAV masters yourself.
Church and community groups
Make sermon, meeting and event recordings small enough to email to members, share in a group chat or post on a simple website.
Settings explained
| Setting | What it does |
|---|---|
| MP3 bitrate | Higher bitrates sound better and make larger files. 96 kbps suits most uses; 64 kbps mono is ideal for voice. |
| Convert to mono | Halves the data for voice recordings, interviews and podcasts. |