Whether you're emailing a recording, uploading a podcast, or just freeing up space, there are four dependable ways to make an audio file smaller. Some are nearly free of any quality cost; others trade a little fidelity for a lot of savings. Here's each one and roughly what it saves.
Bitrate is how much data is used per second of audio, and it's the most direct control over file size. Dropping an MP3 from 320 kbps to 192 kbps cuts the file by about 40% and is inaudible to most listeners; dropping to 128 kbps roughly halves it again and is perfect for speech. If your file is currently a high-bitrate MP3 or an uncompressed format, this is usually the single biggest win. (More on choosing: what bitrate should you use?)
If your file is a WAV, it's uncompressed and therefore very large. Exporting it as an MP3 can shrink it by roughly 90% with little audible difference at a sensible bitrate. This is the classic move for a recording you want to share rather than keep editing — the difference between a bulky studio file and something you can email. (Background: MP3 vs WAV vs FLAC vs M4A.)
A stereo file stores two channels; mono stores one. For a single voice — a podcast, narration or voice memo — the second channel usually adds nothing but size, so converting to mono cuts the file roughly in half with no real loss. Save this one for spoken-word or single-source audio; for music, keep stereo. (Details: mono vs stereo.)
The simplest saving of all: remove what you don't need. Silence at the start and end, long pauses, rambling intros — every second you cut is bytes you don't store. On a long recording, tightening it up can meaningfully shrink the file while also making it better to listen to.
Everything runs locally in your browser, so even a large starting file isn't uploaded anywhere — it's processed on your device.
Converting an uncompressed WAV to MP3 is usually the biggest single drop (around 90%). After that, lowering bitrate and switching to mono each save substantial additional space.
Not if you match the method to the content. Speech at 128 kbps mono sounds clean; music at 192 kbps stereo stays great. Problems only appear if you push the bitrate very low on music.
A trimmed, mono, 128 kbps MP3 of speech is very compact — often around 1 MB per minute or less — while remaining perfectly clear.
Yes — re-exporting the same format at a lower bitrate, converting to mono, or trimming all reduce size without switching formats.
Related: What bitrate should you use? · Mono vs stereo · All guides