Song File Size Calculator

Song File Size Calculator

Planning storage for a music library or podcast archive? This calculator estimates audio file size from duration and bitrate.

File Size (MB) = (Bitrate(kbps) x Duration(seconds)) / 8 / 1024

Example

A 3.5-minute song at 320 kbps:

File Size = (320 x 210) / 8 / 1024 = ~8.20 MB

CBR vs. VBR Encoding

This formula assumes constant-bitrate (CBR) encoding, common in standard MP3 exports. Variable-bitrate (VBR) encoding instead allocates more data to complex passages and less to simple ones, often producing a noticeably smaller file at a similar perceived audio quality.

Planning Storage for a Large Library

Multiplying this per-song estimate by your total track count gives a quick, useful planning figure for cloud storage, backup drives, or streaming bandwidth budgets before committing to a particular bitrate across an entire music collection.