Audio Converter and Compressor
Turn a big WAV into an MP3 or shrink any audio file so it is easy to send and store. You can open WAV, FLAC, AIFF, M4A, OGG and MP3 files, save them as MP3, M4A, Opus, WAV or FLAC, and see exactly how much smaller the new file is.
Drop an audio file here or click to choose one
WAV, FLAC, AIFF, M4A, AAC, OGG, Opus, MP3 and WMA files up to 500 MB all work.
How to Convert WAV to MP3
- Drop your WAV file into the box above, or tap it to pick a file from your computer or phone.
- Leave MP3 selected and choose a quality. 192 kbps is a safe pick for music, and 128 kbps is plenty for speech.
- Press Convert to MP3. When it's done you'll see the old and new sizes side by side, and you can listen to the result before you download it.
The same steps work for FLAC to MP3, AIFF to MP3, M4A to MP3 and the other way round. If you just want a smaller file and don't mind which format it ends up in, Opus gives the smallest file for the same sound quality.
Why WAV Files Are So Big
A WAV file stores every single sample of the sound wave with no compression at all. CD-style audio is measured 44,100 times a second, and a lot of video and game audio uses 48,000. Each measurement takes 2 bytes, and a stereo file has two channels, so one second of 48 kHz stereo audio is 48,000 × 2 × 2 = 192,000 bytes. That works out to about 11.5 MB for every minute, or close to 700 MB for an hour.
An MP3 at 128 kbps uses 16,000 bytes a second, which is about 1 MB a minute. When we ran a one minute 48 kHz stereo WAV of 11.5 MB through this tool, the 128 kbps MP3 came out at 0.96 MB and the 192 kbps MP3 at 1.44 MB. Opus at 96 kbps was about 0.5 MB, which is 23 times smaller than the WAV, and it still sounded clean.
Which Format Should You Pick?
| Format | Type | One minute of stereo | Best for |
|---|---|---|---|
| MP3 | Lossy | 0.9 MB at 128 kbps, 1.4 MB at 192 kbps | Sharing, car stereos and anything old, because every device can play it |
| M4A (AAC) | Lossy | 0.9 MB at 128 kbps | iPhone, iTunes and Apple Music, and it sounds a little better than MP3 at the same size |
| Opus | Lossy | 0.4 to 0.7 MB at 64 to 96 kbps | The smallest files, voice notes, podcasts and the web. WhatsApp and Discord use it |
| FLAC | Lossless | Often about half the WAV size, and less for speech | Keeping a perfect copy of music while still saving space |
| WAV | Uncompressed | 10.1 MB at 44.1 kHz, 11.5 MB at 48 kHz | Editing in programs like Audacity, or apps that only take WAV |
Lossy formats throw away parts of the sound that people are least likely to notice, and that's how they get files ten times smaller or more. Lossless formats like FLAC pack the data more tightly without changing a single sample, so you can turn a FLAC back into the exact original WAV. FLAC files from quiet recordings or speech with lots of pauses can shrink a lot more than music does.
What Bitrate Should You Use?
Bitrate is how much data each second of sound gets, and it's the main thing that decides the size of an MP3, M4A or Opus file. The size is roughly the bitrate times the length, so doubling the bitrate doubles the file. Here's what works well in practice:
- Speech, lectures and voice memos: MP3 at 64 to 96 kbps, or Opus at 32 to 48 kbps. Turning on mono helps here too.
- Podcasts: MP3 at 96 or 128 kbps, which is what many podcast hosts suggest.
- Music for everyday listening: MP3 at 192 kbps, M4A at 128 to 160 kbps or Opus at 96 kbps. Most people can't tell these apart from the original on phone speakers or earbuds.
- Music you care a lot about: MP3 at 256 or 320 kbps, or keep it as FLAC.
One thing to watch is that converting can never add back quality that isn't in the file already. Turning a 128 kbps MP3 into a 320 kbps MP3 or a WAV makes the file bigger but it won't sound any better. It's also best not to convert lossy files over and over, because each pass loses a little more detail. If you have the original WAV or FLAC, always convert from that.
More Ways to Reduce Audio File Size
- Switch to mono for anything with one voice or one instrument. A mono WAV or FLAC is half the size of a stereo one, and lossy formats can use a lower bitrate for the same quality.
- Use Opus if the people you're sending it to have a recent phone or browser. It beats MP3 by a wide margin at low bitrates.
- Cut the silence at the start and end in an editor before you convert, since a minute of silence in a WAV still takes up 10 MB or more.
- Check the length of a file that seems too big. A two hour recording at 128 kbps is still about 115 MB, so for long recordings a lower bitrate makes the biggest difference.
Why Games Have Such Big Audio Files
Games are a good example of how much space audio can take. Some games store their sound effects uncompressed or only lightly compressed, so the game can play hundreds of sounds at once without spending processor time decoding them. When Titanfall came out in 2014, about 35 GB of its 48 GB install was uncompressed audio, which the developers said was done so the game would run well on slower PCs. Voice acting adds even more, because a big game might ship the same hours of dialogue in ten or more languages. Compressing that audio is one of the easiest ways to cut a download down, and it's the same trade you make when you turn a WAV into an MP3 here.
For Developers: the FFmpeg Commands
This tool runs FFmpeg with settings like these, if you'd rather do it in a script:
# WAV to MP3 at 192 kbps
ffmpeg -i input.wav -c:a libmp3lame -b:a 192k output.mp3
# WAV to M4A (AAC) at 128 kbps
ffmpeg -i input.wav -c:a aac -b:a 128k -movflags +faststart output.m4a
# WAV to Opus at 96 kbps
ffmpeg -i input.wav -c:a libopus -b:a 96k output.opus
# Lossless FLAC, and mono at the same time
ffmpeg -i input.wav -ac 1 -c:a flac -compression_level 8 output.flacFrequently Asked Questions
How do I convert a WAV file to MP3 for free?
Drop the WAV file into the converter on this page, keep MP3 selected, pick a quality such as 192 kbps and press Convert to MP3. You can listen to the result and see how much smaller it is before you download it. It is free and you don't need an account.
How much smaller will my file get?
Going from WAV to MP3 usually makes the file about 7 to 12 times smaller. A one minute stereo WAV is around 10 to 11.5 MB, and the same minute as a 128 kbps MP3 is just under 1 MB. Opus can go further, often 20 times smaller or more. Before you convert, the tool shows the expected size next to each quality option.
Will converting to MP3 make it sound worse?
MP3, M4A and Opus are lossy, so a little detail is removed, but at 192 kbps MP3, 128 kbps M4A or 96 kbps Opus most people cannot hear a difference on normal headphones. If you need a perfect copy, choose FLAC instead. It is lossless and still smaller than WAV.
Is Opus better than MP3?
For file size, yes. Opus sounds about as good as MP3 at roughly half the bitrate, and it handles speech especially well, which is why WhatsApp, Discord and most video calls use it. The downside is that some older devices, car stereos and apps cannot play Opus files, so pick MP3 when you are not sure what the listener will use.
Which format should I use for an iPhone?
M4A (AAC) is the safest choice for Apple devices. It plays in the Music app, can be used for ringtones and sounds a little better than MP3 at the same size. MP3 also plays fine on iPhones. Recent versions of iOS can play Opus in some apps, but older iPhones may not.
Can converting MP3 to WAV or FLAC improve the quality?
No. Converting an MP3 to WAV or FLAC keeps it exactly as it sounds now but makes the file much bigger. The detail that MP3 removed is gone for good. It is only worth doing when an editing program or a device needs WAV.
What is the largest file I can convert?
You can convert files up to 500 MB, which is about 45 minutes of 48 kHz stereo WAV or several hours of MP3. Bigger files take longer to upload, so a steady connection helps.
Where are my files processed?
Your file is sent to our server, where FFmpeg converts it and sends the new file straight back to your browser. Both the upload and the converted file are deleted as soon as the conversion finishes.
Related Tools
If your audio is stuck inside a video, pull it out first with the Video to MP3 Converter. You can also shrink the video itself with the Video Compressor, turn a clip into a shareable video with the Audiogram Maker, or make a voiceover from text with Text to Speech.