Shrink an MP3 by preset, exact bitrate, percentage or a target file size in MB, with the output size estimated live and speech files given two extra rescue switches.
Your files are processed in your browser, on your own device. Nothing is uploaded to a server.
Compressing an MP3 means making a file that is too big for its destination fit: the email attachment cap, the upload form limit, the messaging ceiling. This tool runs in your browser and offers four ways to choose the target, including the one that matters most in practice: name the size in MB and let the tool work out the bitrate from your file’s real duration.
First the honesty line, printed before the controls rather than after the complaint. Compressing an MP3 always re-encodes it and always loses something. The output is a smaller, slightly worse copy, every time. Keep the original. Any tool that calls this process near-lossless is describing a different universe.
1. Drop the MP3 files into the box, up to 10 at once.
2. Choose how to set the target: a quality preset, an exact bitrate, a percentage of the source, or a target size in MB.
3. Check the live estimate, then press Compress the MP3.
Presets are the fast road: Music at 192 kbps, Podcast at 128, Speech at 96, Smallest at 64. Exact bitrate is for a spec you were given. Percentage suits a folder of mixed files where halving everything is the goal. Target size is the email-and-forms mode: Gmail and Outlook cap attachments at 25 MB (checked October 2026), Discord’s free tier at 20 MB after its August 2026 change, and typing 24 MB gets you a file that fits instead of a rejected send. When a target forces music down under 64 kbps, the panel warns that the file will fit and sound poor, rather than silently complying. WhatsApp is not used as a size argument here: its document cap is 2 GB, so it rarely needs this tool.
Voice files get two rescue switches that shrink more than bitrate does: fold stereo to mono, and drop the sample rate to 22050 Hz. Together they can quarter a voice recording before the encoder even starts. They are labelled voice-only because music through them sounds like a phone call from 1998.
The engine note: the first job downloads about 31 MB of encoder files once, your browser caches them, and your audio never leaves the device. Estimates for constant bitrate are exact math from the probed duration, shown per file as you change settings, and batch runs apply one setting to up to 10 files with a ZIP back.
For a WAV that needs to become small, this is the wrong page in the right family: wav to mp3 owns the format change with the same bitrate ladder. For other formats entirely, the audio converter is the door. More in the audio tools collection.
Speech stays intelligible and even pleasant down to 64 kbps mono, which is why audiobooks ship there. Music is less forgiving: cymbals turn watery and stereo narrows as the rate drops, and most listeners notice by 96. The ladder on this page follows that reality: it will take a file as small as you demand, and it will tell you when the demand crosses from smaller into worse.
For music, 128 kbps is the cautious floor and 192 is comfortable. For speech, 64 to 96 kbps is fine. Below those, artefacts stop being subtle, and the tool warns when a target size forces them.
It depends on length. The target-size mode exists for exactly this: tell it 24 MB for the 25 MB Gmail and Outlook caps and it computes the bitrate from your file’s duration. Discord’s free tier cap is 20 MB as of its August 2026 change.
Yes, always. It re-encodes at a lower rate and discards sound. The result is a smaller, slightly worse copy. Keep your original file.
Use the WAV to MP3 page: converting the WAV to MP3 is itself the compression, with the same bitrate ladder plus VBR.
For voice files, folding to mono halves the data and dropping to 22050 Hz halves it again, before bitrate is even considered. On music they damage the sound, so they are labelled voice-only.
Yes, up to 10 with the same setting, delivered as a ZIP. The estimate shown is computed from the first file’s duration, and each file’s own duration drives its own target math.
Same rules as this one: free, in your browser, with nothing uploaded.
MP3, WAV, M4A and OGG, swapped in seconds.
Cut a ringtone or a clip out of any song.
Heavy WAV files made small enough to share.
Voice memos and iTunes files as plain MP3s.
An MP3 opened back up into a full WAV file.
OGG files, often from games and apps, as MP3s.
Big FLAC songs made small enough for a phone.
An MP3 saved as OGG for games, apps and the web.