Compress FLAC

FLAC is already compressed, so the savings come from a lower bit depth, mono or a lossy copy. All three are here.

or drop them here

MP3, WAV, M4A, FLAC, OGG, Opus, AIFF, WMA, AMR and the sound of most videos. Files stay on your device.

How it works

Choose your FLAC files.
Pick a lossless option (16-bit, mono, lower sample rate) or a lossy format.
Click Compress and compare sizes.
Download the results.

FLAC is already compressed

FLAC stores audio without losing any of it and is usually half the size of the same WAV. That makes it hard to shrink further without changing the audio. The browser’s FLAC encoder uses a fixed compression level, so re-saving a FLAC file barely changes its size, and this page does not pretend otherwise.

The real savings come from three choices: a lower bit depth (24-bit to 16-bit removes a third of the raw data), mono or a lower sample rate, or a lossy format.

Lossless or lossy

Keep FLAC output for archives and editing: every sample you save is the sample you get back, apart from the depth, channel or rate reduction you asked for. Convert to MP3, M4A, Opus or OGG when the file is for listening or sharing: a FLAC song of 30 MB becomes about 3 MB at 128 kbps. Target size mode needs a lossy format, because a lossless file cannot be fitted to an exact size.

Questions

Why does a re-saved FLAC come out the same size?

FLAC already packs the audio about as well as it can, and the encoder here uses one fixed level. Lowering the bit depth, using mono or lowering the sample rate removes data, which is what makes it smaller.

Is 24-bit to 16-bit audible?

Rarely. Dither is added when reducing the depth so the rounding stays inaudible. Keep the 24-bit original for editing.

Which lossy format should I use for FLAC files?

MP3 plays anywhere; M4A (AAC) and Opus give better quality at the same size. At 128 to 192 kbps the difference from FLAC is hard to hear for most listeners.

Is my audio uploaded?

No. Compression runs in your browser on your device. The only downloads are the page itself and, the first time you use a format, a small encoder file from this site.