How audio compression actually works here
Audio size is mostly a function of one number: bitrate, measured in kbps. A higher bitrate stores more detail per second of sound, which makes the file bigger. This tool re-encodes your audio to a constant MP3 bitrate you choose, so a 320 kbps file dropped to 96 kbps comes out roughly a third of the size. It is a one-way trade — you are discarding data to save space — so you cannot get the lost detail back by re-encoding upward later. Pick the lowest bitrate that still sounds acceptable for how the file will be used, and keep the original if you might need it again.
Bitrate vs. quality: speech vs. music
The right setting depends entirely on the content. Spoken word — voice memos, interviews, podcasts, screen-recording narration — survives aggressive compression. 64 kbps or 96 kbps is usually indistinguishable for speech because voices occupy a narrow frequency band. Music is the opposite: cymbals, reverb tails, and bass need more headroom, so 128 kbps is a sensible floor and 192 kbps is close to transparent for most listeners. If you are not sure what is in the file, 96 kbps is a safe default that almost always shrinks things meaningfully without an obvious quality hit.
Getting under email and Discord limits
Most of the people who land here have a hard size ceiling to clear. Gmail rejects attachments over 25 MB. Discord caps uploads at 25 MB for free users. Many forms and CMS uploaders set their own limits. The math is simple: file size in MB is roughly bitrate (in kbps) times duration (in minutes) divided by 133. So a 60-minute recording at 96 kbps lands near 43 MB — still too big for Gmail, so drop to 64 kbps to get it under the line. If you need to share something far easier than wrestling with attachments, record it with Clipy and send a hosted link instead — no size limit, no compression compromise on the other end.
Why the output is always an MP3
Whatever you feed in — WAV, M4A, AAC, OGG, FLAC, or an already-MP3 file — you get an MP3 back. That is deliberate. MP3 is the one format every player, browser, phone, and chat app understands without a plugin, and it compresses far better than uncompressed WAV or FLAC. A lossless WAV converted to a 96 kbps MP3 can shrink by more than 90%. If your source was already a low-bitrate MP3, picking a higher bitrate would only make the file bigger without adding quality, so this tool refuses to hand you an output that is larger than the input.