What size reduction can I expect?

Depending on the source format, you can reduce size up to 90%. A WAV can be compressed to MP3 128kbps with 80-90% reduction.

What is the difference between lossy and lossless compression?

Lossy compression (MP3, AAC, OGG) removes inaudible or barely perceptible sound information from the file — much smaller but the original signal cannot be recovered. Lossless compression (FLAC, ALAC) reduces size via pure entropy coding — playback is bit-for-bit identical to the source. Use lossless for archival, lossy for delivery.

What bitrate (kbps) should I choose to stay audibly transparent?

For music in MP3, 192 kbps is the commonly accepted threshold for transparency on everyday hardware; 256 or 320 kbps guarantee transparency on HiFi equipment. For spoken voice (podcast, audiobook), 96 to 128 kbps mono is plenty. In AAC, you can go 32 kbps lower than MP3 for equivalent quality.

Does compression degrade an already-compressed file (re-compression)?

Yes, re-compressing an MP3 into a lighter MP3 stacks the losses of both passes — each cycle removes a bit of perceptible quality. Our tool warns you when the source is already lossy and suggests re-encoding from a lossless original if you have one. If not, keeping the target bitrate equal to or higher than the source strongly limits visible loss.

Can I compress a stereo file to mono to save even more space?

Yes, the "force mono" option roughly halves the size by merging the left and right channels. Useful for a voice recording, a podcast, an interview, or a dictaphone track — stereo brings nothing. Do not use it on music or a produced stereo mix: the stereo image (instrument placement) is definitively lost.

Compress an audio file

Reduce an audio file’s size by adjusting compression to balance file weight with the sound quality you want to keep.

Drag and drop your audio files

or click to select (MP3, WAV, FLAC, OGG, AAC, M4A)

Supported formats

MP3

WAV

FLAC

OGG

AAC

How to use

Drag and drop your audio file

How to use

Choose your desired compression level

How to use

Download your compressed audio

Privacy

This tool processes audio in your browser. Account, analytics and advertising services on the site are separate from audio-file processing.

Reduce MP3 file size

Optimize your MP3 files for email or mobile storage. Our compressor reduces file weight while preserving optimal audio quality for everyday listening. For Reduce MP3 file size, compare the result with the source file and treat Compress an audio file as a controlled step: listen to a representative passage before keeping the final download.

Compress a raw WAV to MP3 for email attachments

A one-minute WAV recording weighs about 10 MB — too heavy for most email servers (25 MB limit is common). Compressing it to MP3 at 192 kbps drops the file to about 1. 5 MB for the same minute, with quality indistinguishable on standard speakers or headphones. You can then email several minutes of audio without going through WeTransfer or Google.

Shrink a podcast to host it at lower cost

For a one-hour podcast, a WAV weighs 600 MB, an MP3 at 128 kbps mono only 55 MB. Across 100 hosted episodes, the difference is over 50 GB of bandwidth per month — a direct cost on most hosting providers. Compressing to 96 kbps mono for spoken voice stays completely clean, with no sibilance or perceptible artifact.

Slim a music library for a smartphone

On a 128 GB smartphone, usable space is quickly eaten by photos and apps. Recompressing a 30 GB FLAC or WAV library to MP3 320 kbps brings it down to 6-8 GB — over 20 GB freed for photos and videos, with no audible degradation over Bluetooth or with standard headphones. The original format is kept on your PC or NAS for HiFi listening at home.

Compress sounds for a website or mobile app

On a website or app, every kilobyte counts for load time and mobile data. UI sounds (notification, click, alert) compressed to MP3 32 kbps mono or OGG 48 kbps remain perfectly identifiable while weighing just a few kilobytes. For an HTML5 game, audio compression is often the first performance win, before even image compression.

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Reduce MP3 file size

Compress a raw WAV to MP3 for email attachments

Shrink a podcast to host it at lower cost

Slim a music library for a smartphone

Compress sounds for a website or mobile app