Compress Audio Files: Make MP3, WAV & M4A Smaller
Compress audio files to a fraction of their size by lowering the bitrate, switching speech to mono or moving to the more efficient AAC (M4A) or Opus formats. The estimated output size updates before you press the button, so you know whether a recording will fit in an email or an upload form. It works on MP3, WAV, M4A, FLAC and more, in your browser, with no upload.
- Runs on your device
- WebCodecs · GPU
- FFmpeg
- Works offline
Updated
Drop your audio files here
How to compress an audio file
Step 1: Drop one or more audio files on the box above.
Step 2: Pick a Format: MP3 for compatibility, M4A (AAC) or Opus for the best sound at small sizes.
Step 3: Choose a Bitrate and, for speech, set Channels to Mono. Watch the size estimate as you change them.
Step 4: Press Compress and download the smaller files.
Good to know
Settings explained
- Format
- Opus and AAC sound better than MP3 at low bitrates.
- Bitrate
- 64 kbps is fine for speech; 128 kbps for music.
- Channels
- Mono halves the bitrate needed for speech.
Formats
Batch-friendly: add many files and they are processed one after another — if one fails, the rest still finish.
How it runs
- Hardware video engine
- Video is decoded and encoded by your device’s media hardware through WebCodecs — usually several times faster than real time.
- FFmpeg (when needed)
- Older formats and a few filters use FFmpeg compiled to WebAssembly. It downloads once (about 31 MB) the first time it is needed and is cached for offline use.
How small will the file be?
Size depends only on bitrate and length: kilobits per second × seconds ÷ 8. That makes it predictable. The table shows one hour of audio at each bitrate, and how much fits under common attachment limits, so you can choose before you compress.
| Bitrate | One hour | Fits in 25 MB (Gmail) | Fits in 20 MB (Discord free) |
|---|---|---|---|
| 48 kbps | 21.6 MB | 69 min | 55 min |
| 64 kbps | 28.8 MB | 52 min | 41 min |
| 96 kbps (default) | 43.2 MB | 34 min | 27 min |
| 128 kbps | 57.6 MB | 26 min | 20 min |
| WAV, CD quality (for comparison) | 635.0 MB | 2 min | 1 min |
How to reduce the size of an audio file without losing quality
Every real size reduction on lossy formats removes something, so the goal is to remove what nobody will hear. Three moves do most of the work.
Use mono for speech: a voice recorded in stereo is the same sound twice, and mono lets 48–64 kbps sound clear. Use a better codec: Opus and AAC sound noticeably better than MP3 at 64 kbps and below. Match the bitrate to the content: 96–128 kbps AAC or Opus is plenty for most music, 48–64 kbps for talk.
If you need truly lossless compression, convert WAV to FLAC in the audio converter instead; it typically saves a third to a half of the size with zero loss.
How do I compress an MP3 to a specific size, like 1 MB or 16 MB?
Work out the bitrate from the length: bitrate (kbps) = size in MB × 8,000 ÷ length in seconds. For a 3-minute (180 s) song to fit in 1 MB, that is 1 × 8,000 ÷ 180 ≈ 44 kbps, so choose 48 kbps mono or trim the song. For a 30-minute talk to fit in 16 MB, 16 × 8,000 ÷ 1,800 ≈ 71 kbps, so choose 64 kbps. The size estimate confirms it before you compress.
The compressor does not have an automatic “fit to N MB” mode yet. If the file is still too big at 48 kbps, shorten it with the MP3 cutter or cut the pauses with remove silence.
Is an audio compressor the same as dynamic range compression?
No. In music production a “compressor” narrows the gap between loud and quiet parts. This page compresses the file size. ProMedia has no dynamic range compressor; to bring several recordings to one loudness, use normalize audio, and to raise a quiet file without clipping, the volume booster.
What is the smallest bitrate that still sounds good?
| Content | Format and bitrate | Channels |
|---|---|---|
| Voice notes, lectures, phone calls | Opus or M4A, 48 kbps | Mono |
| Podcasts and audiobooks | M4A or Opus 64 kbps, or MP3 64–96 kbps | Mono |
| Background music, demos | M4A or Opus 96 kbps | Stereo |
| Music you care about | Any format at 128 kbps or more | Stereo |
Tips & troubleshooting
Compressing a WAV? Even 128 kbps MP3 is about eleven times smaller than CD-quality WAV; WAV to MP3 has the higher bitrates too.
Opus files are always 48 kHz and play in browsers and on Android; pick MP3 if the recipient might use an old player.
Compressing a video’s soundtrack? Shrink the whole video with the video compressor instead.
Recompressing an already small MP3 rarely helps: going from 64 to 48 kbps saves 25% and costs clarity.
Audio Compressor FAQ
How can I reduce the size of an audio file without losing quality?
For lossless savings, convert WAV to FLAC. For bigger savings with no audible loss, use AAC or Opus at 96–128 kbps for music, or 48–64 kbps mono for speech. Most of a voice recording’s size is data you never hear.
How do I compress an audio file for email?
Gmail allows 25 MB per message. At 64 kbps that is about 52 min of audio, at 96 kbps about 34 min. Pick the bitrate, check the size estimate, then press Compress.
How do I compress an audio file for WhatsApp?
Choose M4A or Opus at 48–64 kbps with Channels set to Mono. A one-hour talk then comes to roughly 22–29 MB and a few minutes of voice to well under 2 MB, small enough to send quickly on mobile data.
Can I compress WAV files?
Yes. WAV is uncompressed, so it shrinks the most: one hour of CD-quality WAV is about 635 MB, and the same hour at 96 kbps is about 43 MB. For a lossless smaller file, convert to FLAC instead.
Is the audio uploaded to compress it?
No. Compression runs in your browser on your device, so private recordings stay private and there is no file-size cap.