How do I compress mp3 audio file to small size?

I had the same problem earlier. CD-ripped MP3s are usually very high bitrate, so they end up huge (30MB+ for a single track). The easiest way to reduce MP3 size is to lower the bitrate, not just “zip” the file.

If you don’t want to install heavy software, you can use a simple MP3 audio compression tool that lets you choose the output bitrate (like 128 kbps or 96 kbps). This usually reduces file size by 5–10x and still sounds perfectly fine for car audio systems.

I personally used this guide to compress MP3 audio files step-by-step, including batch compression and quality tips:

•  compressexcel dot com audio

Quick tips from experience:

128 kbps = good balance for sharing & car players

Always keep the original files as backup

Test 1–2 files before batch compressing

This worked well for me when my car stereo couldn’t read large MP3 files. Hope it helps