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WAV to MP3.
The normal last step. Do it from the WAV, never from another MP3. A WAV is around 10 MB a minute, which fills a stick fast and is far more than you need for playback. Encoding to 320 kbps cuts it to roughly a tenth and, because the source is uncompressed, this is the cleanest kind of MP3 there is.
Drop tracks to convert
WAV, AIFF, FLAC, MP3 or M4A. Drop a whole folder’s worth — one set of settings is applied to all of them and they come back as a single archive. Nothing is uploaded; the page makes no network request.
What it costs
You are throwing audio away.
The part every other converter leaves out, because it is the part that sometimes says don't.
Audio you cannot get back. Keep the WAV — a mix you might re-edit, a master you might re-cut, a bounce you might re-normalise all need the lossless file. The MP3 is a delivery copy, not an archive.
MP3 plays on everything — every CDJ, every controller, every laptop, every pool download. That universality is the entire reason to make one.
The four that matter
What each format is for
Ogg and Opus are missing on purpose: no CDJ reads either, so neither belongs in a DJ's library.
| Format | Size, roughly | What it is for |
|---|---|---|
| WAV | 10 MB a minute | Uncompressed and universal. Opens in everything ever written. Poor at holding tags, which is the one reason to prefer AIFF. |
| AIFF | 10 MB a minute | The same audio as WAV in a container that tags properly. What Rekordbox is happiest with and what every CDJ in service reads. |
| FLAC | About two-thirds of WAV | Lossless compression — identical samples, a third less disk, and a checksum so the file can prove it years later. Read by Rekordbox and the CDJ-3000, but not by the CDJ-2000NXS2. |
| MP3 | About 2.4 MB a minute at 320 | Lossy, permanent, and universal. The right last step for a stick and the wrong middle step in any chain. |
The rule underneath all of it: lossless to lossless costs nothing and can be undone, lossless to lossy costs audio you cannot get back, and lossy to lossless costs disk and recovers nothing. Only the middle one is a real decision.
Frequently asked
Common questions
What is the best bitrate to convert WAV to MP3?+
320 kbps for anything you are going to play out. It is the most an MP3 can carry, a four-minute track lands around 9 MB, and on a club system the difference from the WAV is genuinely hard to find. Drop to 192 and the top end starts to sound glassy on a big rig; 128 stops carrying content at around 16 kHz, which is a preview rather than a record.
Can I convert the MP3 back to WAV later?+
You can produce a WAV from it, but it will not be the WAV you started with — the audio the encoder discarded is gone and unwrapping it into a bigger container does not bring any of it back. This is the most common misunderstanding about audio formats and it is worth being blunt: a big file is not a good file. Keep the original.
Does this work on a whole folder of mixes?+
Yes. Drop as many files as you like and one setting is applied to all of them, with a report per file and the results as a single archive. Encoding is real work — several times faster than playing the track, not instant — so a folder of long recordings takes a few minutes rather than seconds.
Do my files get uploaded anywhere?+
No, and that is the main reason to use this rather than a site that asks you to wait for an upload. The WAV is decoded, re-written as MP3 and handed back entirely inside this browser tab — open the network panel and watch it stay empty. There is no server behind the page, which means an unreleased promo is safe to drop on it and nothing is sitting in somebody's bucket afterwards.
Can I convert a whole folder at once?+
Yes. Drop as many files as you like, set the format once, and the whole queue is converted with a report for each file — what it came from, what it went to, and how the size compares. The results come back as a single archive rather than as thirty separate downloads, which is what you want when the next step is dragging a folder into Rekordbox.
Do the tags come across?+
Yes. Artist, title, album, album artist, genre, year, track number, label, remixer, composer, BPM, key, ISRC, comment and the cover art are all read off the WAV and written into the MP3, so a converted folder arrives in Rekordbox named rather than as a wall of filenames. The one thing that does not travel is anything a DJ program keeps in its own private frames — Serato's cue points and beat grid live in an undocumented block that nothing outside Serato reads, and no converter can carry them.
Is there a file size limit?+
Up to 800 MB per file, which is about 75 minutes of 24-bit stereo audio — a full recorded set fits comfortably. Past that it is the browser's own decoder that gives up rather than the tool.
How does this tool make its FLAC and MP3 files?+
The lossless formats are written here, and verified: every test file was decoded again by an independent decoder and compared sample by sample against the original, with zero differences. On real records the FLAC comes out at about 67% of the uncompressed size, which sits between the standard encoder's default setting and its slowest one. MP3 uses the reference encoder that has been the answer to that problem for twenty-five years, because a homemade one would not make bigger files, it would make worse-sounding ones.
Other conversions
WAV to FLAC · WAV to AIFF · FLAC to MP3 · AIFF to MP3 · M4A to MP3 · Every direction
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DJ terms on this page: FLAC · Lossy compression · Bit rate · WAV and AIFF · Sample rate · Lossless · CDJ · Full glossary