Guide1 min readUpdated August 12, 2026
How to compress an MP3
Short answer
To compress an MP3, re-encode it at a lower bitrate: 128 kbps is a good balance for speech and casual music, 96 kbps or less for voice-only. Lower bitrate means a smaller file and some quality loss, so pick the lowest that still sounds acceptable.
Bitrate is the main lever
An MP3's size is set mostly by its bitrate — the data used per second of audio. Halving the bitrate roughly halves the file. The trade is quality, so the goal is the lowest bitrate that still sounds good enough for how the file will be used.
Pick a bitrate for the job
- 320 kbps — near-transparent music; largest files
- 192 kbps — a good default for general music
- 128 kbps — fine for casual listening and most sharing
- 96 kbps or less — voice, audiobooks, and podcasts
Steps
- Start from the best sourceCompress from the original, not an already-shrunk copy — re-compressing lossy audio loses more each time.
- Choose a lower bitrateStep down until the file is small enough. For speech, mono at a low bitrate saves a lot with little audible loss.
- Listen before you commitCheck a section with music or detail. If it sounds thin, move one step back up.
Codec vs bitrateIf you control the playback target, converting to a more efficient codec can beat MP3 at the same size. For universal compatibility, a lower-bitrate MP3 is the safe way to shrink a file.
Try it: MP3 CompressorReduce an MP3's size by choosing a lower bitrate, locally in your browser.Open tool