Guide to Bitrate Selection for Compressing WAV Recordings to MP3
A single minute of uncompressed WAV recording can reach 10MB in size. Converting to MP3 can reduce the file size by approximately 90%. This article explains how to calculate file size and select a suitable bitrate for conversion.
Updated 2026-08-11
How to Calculate the Original File Size of WAV
WAV uses uncompressed PCM storage. The bitrate calculation formula is: bitrate = sample rate ร bit depth ร number of channels. After unifying all units to bits, you can get the data volume per second.
CD-standard WAV has a sample rate of 44100Hz, 16-bit depth, and 2 channels. Calculation shows that the size of one minute of this WAV is approximately 10MB, and one hour of recording can reach 600MB.
Most WAV recordings generated by mobile phones use the same parameters as CD-standard WAV, and are subject to single-file size limits during sharing and uploading, so compression processing is required.
Comparison of Sound Quality and File Size for Different MP3 Bitrates
MP3 is a lossy compression format that reduces file size by removing signals insensitive to the human ear. The output file size is directly determined by the output bitrate: the higher the bitrate, the closer the sound quality is to the original file.
Below is the comparison of file size per minute and sound quality performance for different MP3 bitrates:
| MP3 Bitrate | Size per Minute |
|---|---|
| 128kbps | ~0.96MB |
| 192kbps | ~1.44MB |
| 256kbps | ~1.92MB |
| 320kbps | ~2.4MB |
Compression Parameter Selection for Voice Recordings
For voice WAV recordings such as meetings, interviews, and online courses, the core information is human voice signals in the range of 1kHz to 3.5kHz. A 128kbps bitrate can meet the requirements of recognition and clear listening.
Most recording scenarios do not require dual-channel capture. Converting a stereo WAV to a mono MP3 can directly halve the file size while keeping the bitrate unchanged, resulting in a more significant size reduction.
When converting a voice recording to 128kbps mono MP3, the size per minute is only 0.48MB, and one hour of recording is less than 30MB, which meets the upload requirements of most platforms.
Compression Parameter Selection for Music WAV Recordings
WAV recordings that contain background music and singing need to retain more high-frequency details, so the bitrate requirement is higher than that of pure voice recordings.
For daily sharing needs, a bitrate of 192kbps to 256kbps is suitable. This provides reasonable size control and meets the sound quality requirements for external playback scenarios. For scenarios with higher requirements for sound quality, you can select the highest MP3 specification of 320kbps, which delivers sound quality close to the original file.
Related tools
FAQ
Will there be sound quality loss when converting with OKfmt's WAV to MP3 converter?
Converting to MP3 is a form of lossy compression, so some signal loss is unavoidable. This tool uses the standard LAME encoding engine, and its parameter matching complies with current general specifications. The final sound quality is determined by the output bitrate you select.
Can compressed WAV be converted back to lossless WAV?
It is not possible to restore a WAV with the original sound quality. The MP3 compression process has already removed part of the information from the original WAV, and the deleted signals cannot be recovered after decoding and restoration.
Why not use lossless formats such as FLAC to compress WAV?
Compressing WAV with a lossless format only reduces the file size by approximately 50%, which is a much smaller reduction than MP3. Most sharing and uploading scenarios do not require lossless sound quality, so MP3 has a more obvious advantage in file size.