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FLAC to AIFF.
Lossless, and the right target if the file is going into Rekordbox. FLAC is the better way to store a collection and AIFF is the better way to play one. If you buy lossless and your library lives in Rekordbox, this is the conversion that gets you a first-class file on every CDJ in service — including the older ones that will not read FLAC at all.
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
Nothing is lost here.
The part every other converter leaves out, because it is the part that sometimes says don't.
Disk, and only disk. The audio is identical. An AIFF is roughly half again the size of the FLAC it came from, which is the price of a container that every deck reads without thinking about it.
AIFF is the format Rekordbox is happiest with: it analyses fast, it carries proper tags, and every CDJ in service reads it. It is the same audio as WAV in a different wrapper, so it costs nothing to prefer it. FLAC is read by the CDJ-3000 and by Rekordbox, but not by the older CDJ-2000NXS2 — so a stick built in FLAC will play on a new booth and not on a five-year-old one. If you do not know what is in the booth, that is the argument for AIFF or WAV.
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
Is anything lost converting FLAC to AIFF?+
No. Both are lossless, so the samples are identical — this is repackaging, not re-encoding. The only thing that changes is the size on disk and which machines will open it.
Why convert to AIFF rather than just playing the FLAC?+
Because of what is in the booth. The CDJ-3000 reads FLAC and the CDJ-2000NXS2 does not, so a stick built entirely in FLAC is a stick that works in some clubs and not others. AIFF works everywhere and costs you nothing but disk, which makes it the safe default for anything leaving the house.
Does AIFF analyse faster in Rekordbox?+
It is the format Rekordbox handles most comfortably, and it carries tags properly, which is the part people notice — a WAV library that loses its artist names is a familiar and avoidable annoyance. If you are converting a collection for Rekordbox, AIFF is the one to pick.
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 FLAC is decoded, re-written as AIFF 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 FLAC and written into the AIFF, 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
FLAC to MP3 · FLAC to WAV · WAV to AIFF · M4A to AIFF · MP3 to AIFF · Every direction
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