Audacity Forum

If one can ... how can one reduce .mp3 file size in Audacity Stable?

You need to configure the MP3 encoder options for LAME to reduce the bitrate. Unfortunately I don't have Audacity on this machine to tell you the exact menu options, but I think it's under "Configure".

Ideally you would not only reduce the bit rate, but also enable Variable Bit Rate (VBR) encoding, assuming your target device supports it. Unfortunately I haven't found out how to do this through Audacity yet.

Regards: Colin

In Audacity 1.2.6 click on ....

Edit (menu)
Preferences
File Formats
MP3 Export Setup - Bitrate - Select a value from 16 to 320 (thousand bits per second)
OK

Audacity will remember the selected bitrate for all future mp3 exports, until you change it again.
Selecting a small value such as 32 will reduce mp3 file sizes, but will also reduce the mp3 sound quality.