Ask ten audio people which format is best and you will get ten opinions, mostly because they are answering different questions. One is thinking about a podcast, another about a studio recording, a third about a phone with limited storage. The sensible answer depends on what you will do with the file. Here is how I think about it, with real numbers.
The basic difference
WAV stores sound without compression. It is a faithful copy of the signal, which is why it is the format of recording studios. MP3 compresses the sound by removing parts that human hearing is unlikely to notice, and by doing so it makes files roughly ten times smaller. One is exact and large, the other is small and slightly reduced.
How big is the difference?
CD-quality stereo WAV uses about 10 MB per minute. A three-minute song is about 30 MB, and an hour-long recording is around 600 MB. The same hour as a 128 kbps MP3 takes about 58 MB, and at 320 kbps about 144 MB. For a phone with limited space, or for sending a file by email, that difference is decisive.
Does MP3 sound worse?
At low bitrates, yes, and the problems are audible: dull treble, swishy cymbals and a thin, watery feel. At 192 kbps, most listeners cannot tell the difference between MP3 and the original in everyday listening. At 256 to 320 kbps, only trained listeners with good equipment in a quiet room succeed in telling them apart reliably. For speech, even 96 to 128 kbps is usually fine.
When to choose WAV
- You will edit the audio. Cutting, adjusting volume and adding effects are all kinder to an uncompressed file, and you avoid compressing the sound twice.
- You are archiving something important. A family recording, an interview or a musical performance you want to keep in its best form.
- You are handing the file to a sound engineer or a studio. They will ask for WAV.
When to choose MP3
- Listening on a phone, in a car or on a portable player.
- Sharing by email or messaging. Small files travel quickly and fit attachment limits.
- Publishing a podcast or a lecture. Speech at 96 to 128 kbps mono sounds good and keeps downloads light.
- Anywhere storage or data costs matter.
The mistake that wastes space
Converting an MP3 to WAV does not restore quality. The WAV will be ten times larger, and it will sound exactly like the MP3, because the removed detail is gone for good. The same is true for the MP3 you make from a video: the source sets the ceiling. If the original audio in a video is a low-quality phone recording, a 320 kbps MP3 will simply reproduce that low quality at a larger size.
Mono or stereo?
For speech, mono is usually enough, and it halves the size. Interviews, lectures and voice notes rarely benefit from two channels. For music, stay with stereo, since the spatial feel is part of the experience.
Choosing a bitrate by purpose
- 96 kbps: spoken word, where small size matters most.
- 128 kbps: general speech and casual listening.
- 192 kbps: a comfortable choice for music on a phone.
- 320 kbps: the highest MP3 setting, for music you care about.
A listening test you can do at home
Instead of trusting numbers, try this once. Take a song you know well and make three copies at 64, 128 and 320 kbps. Play them on the headphones you normally use, and listen to cymbals, the breath of the singer and the quiet moments between notes. Most people hear the 64 kbps copy clearly as worse, hesitate between 128 and 320, and then realise that 128 is fine for their ears and equipment. Your result matters more than any rule, since it reflects how you really listen.
What about other formats?
You may also meet AAC, FLAC and OGG. AAC is the format behind many streaming and phone recordings, and it sounds slightly better than MP3 at the same size. FLAC is lossless like WAV, but compressed to about half the size, which makes it popular for music collections. For sharing with other people, MP3 remains the one that plays everywhere, and that reliability is its main advantage.
Making the file you need
If you have a video and want its sound, the MP4 to MP3 converter lets you choose MP3 or WAV and set the bitrate. The conversion happens in your browser, so your recording stays on your own device. The guide on extracting audio from video on this site has more detail on the steps.
A simple rule of thumb
Keep WAV only when you will edit something, or when it is a one-time recording that cannot be repeated. Everything else can become an MP3 at 192 kbps for music, or 128 kbps for speech. Following that rule saves a great deal of storage over time. If you are unsure, make an MP3 now and keep the original video, so that you can always produce a WAV later.