Reviewed 2026-10-20 by the Spool editorial team · How we test
Why WAV files are so big
WAV stores audio uncompressed: every sample, for every channel, as a plain number. CD-quality stereo (16-bit, 44.1 kHz) takes 1,411 kbps, about 10 MB per minute. A 24-bit, 48 kHz recording from a DAW or field recorder takes 2,304 kbps, about 17 MB per minute. That's ideal while you're recording and editing, and unnecessary when you just want to listen or share.
MP3 uses a psychoacoustic model: it removes sound the human ear is unlikely to notice, such as quiet tones masked by louder ones. At 192 kbps, a WAV becomes about 86% smaller; at 128 kbps, about 91%.
| Format | Bitrate | One minute | A 4-minute song |
|---|---|---|---|
| WAV 24-bit / 48 kHz | 2,304 kbps | ≈ 17.3 MB | ≈ 69 MB |
| WAV 16-bit / 44.1 kHz | 1,411 kbps | ≈ 10.6 MB | ≈ 42 MB |
| MP3 320 kbps | 320 kbps | ≈ 2.4 MB | ≈ 9.6 MB |
| MP3 192 kbps (default) | 192 kbps | ≈ 1.4 MB | ≈ 5.8 MB |
| MP3 128 kbps | 128 kbps | ≈ 1.0 MB | ≈ 3.8 MB |
| MP3 64 kbps mono | 64 kbps | ≈ 0.5 MB | ≈ 1.9 MB |
The encoder and settings
We encode with LAME, the reference open-source MP3 encoder, at a constant bitrate. Constant bitrate gives predictable sizes and the widest compatibility: every MP3 decoder, from car stereos to old iPods, handles it. Settings:
- Audio bitrate (64–320 kbps, default 192). Use 256–320 for music masters you'll distribute, 192 for general listening, 96–128 for speech.
- Channels: choose Mono for single-microphone voice recordings. It sounds identical for speech and gives the encoder twice the bits per channel.
- Sample rate: leave on Original. Pick 44.1 kHz if a distributor demands it; choose 22 kHz only for low-bandwidth voice files.
Bit depth doesn't exist in MP3, so 16-, 24- and 32-bit float WAVs all convert the same way. Text tags stored in the WAV (title, artist) are copied as ID3 tags when present.
Who converts WAV to MP3
- Musicians and producers: send a mix to bandmates or clients for review without a 60 MB attachment. Keep the WAV as your master.
- Podcasters: most hosts recommend MP3 at 96–128 kbps for spoken word, mono or stereo depending on the show.
- Voice recorder users: many recorders and Windows' Sound Recorder save WAV; MP3 makes those files easy to email.
- Sound-effect libraries and game assets that need a lightweight preview format.
Don't edit MP3s and re-save them repeatedly
Each MP3 encode throws information away, and the losses add up across generations. If you'll keep editing, keep working on the WAV and export a fresh MP3 at the end. Need lossless but smaller? WAV to FLAC halves the size with no quality loss at all.
Limits
Convert and edit files on your device. The browser edition accepts up to 100 MB total, media up to 10 minutes and video up to 4K. Codec availability and device memory can limit individual jobs.
Troubleshooting
| Problem | Fix |
|---|---|
| MP3 sounds "swirly" or thin | The bitrate is too low for music. Use 192 kbps or higher. |
| Recording is too quiet | Run the MP3 or WAV through Normalize audio or the volume booster. |
| Need Apple's format | Use WAV to M4A (AAC), which sounds better than MP3 at the same bitrate. |