Key tags: where the key is stored and how DJ software reads it
You want to analyse a track once and see the same key in every program. The way to get there is to keep the key in the file's tag, not only in one program's database. This guide explains how tags work and how the notations convert.
Updated: October 2026
01Database or tag?
DJ software can keep analysis results in two places: its own library database and the tag inside the file. Database information only shows up in that program on that computer. When you move a file to another program, another computer or a USB stick, only the tag travels with it.
Writing key and BPM into the tag makes your library independent of any one program: whether you use Rekordbox today and Serato tomorrow, the keys come with you.
02Which field in which format?
- MP3: the
TKEY(key) andTBPM(tempo) frames of the ID3v2 tag. - FLAC:
INITIALKEYandBPMin the Vorbis comments. If a file has bothKEYandINITIALKEY, some programs may read neither; a single clean field is safest. - AIFF and WAV: both can carry an ID3 chunk, but support for reading it varies between programs. If you rely on tags, prefer MP3, FLAC or AIFF; don't count on WAV tags.
CrateKeys writes the key in classic notation (for example Am) to the key field of MP3 and FLAC files, the BPM to the tempo field, and adds a note such as 08A · Am to the comment. The leading zero makes 1A sort before 10A when you sort by comment. Audio, artwork and other tags are left untouched.
03Notations: 1A, Am and Open Key
The same key can be written three ways: alphanumeric (8A, the layout used by Rekordbox and Camelot), classic (Am) and Open Key (1m, Traktor's default). Open Key shifts the numbers and uses m (minor) and d (major). The table below maps all 24 keys.
| 1A–12B | Classic | Open Key | Key name |
|---|---|---|---|
| 1A | Abm | 6m | A♭ minor |
| 1B | B | 6d | B major |
| 2A | Ebm | 7m | E♭ minor |
| 2B | F# | 7d | F♯ major |
| 3A | Bbm | 8m | B♭ minor |
| 3B | Db | 8d | D♭ major |
| 4A | Fm | 9m | F minor |
| 4B | Ab | 9d | A♭ major |
| 5A | Cm | 10m | C minor |
| 5B | Eb | 10d | E♭ major |
| 6A | Gm | 11m | G minor |
| 6B | Bb | 11d | B♭ major |
| 7A | Dm | 12m | D minor |
| 7B | F | 12d | F major |
| 8A | Am | 1m | A minor |
| 8B | C | 1d | C major |
| 9A | Em | 2m | E minor |
| 9B | G | 2d | G major |
| 10A | Bm | 3m | B minor |
| 10B | D | 3d | D major |
| 11A | F#m | 4m | F♯ minor |
| 11B | A | 4d | A major |
| 12A | Dbm | 5m | C♯ minor |
| 12B | E | 5d | E major |
04Rekordbox
Rekordbox reads tags when you add files to the collection. If the tracks are already in your collection and their tags changed later, select them, right-click and choose Reload Tag. To see 1A–12B in the key column, set the key display format to Alphanumeric in the preferences. Rekordbox can also run its own analysis; if key detection is on in the analysis settings, it may show its own result instead of the tag, so check that setting.
05Serato and Traktor
Serato DJ reads the key field from the tag and shows it in the Key column; if key detection is on during analysis, it may write its own result. Traktor shows Open Key by default; you can switch to classic notation in the preferences. Menu names change between versions in both programs, so look for the "key" and "analysis" settings.
The general rule: decide the key from one source, write it to the tag, and turn off key re-analysis in your DJ software. Then the same track shows the same key everywhere.
06Batch tagging, step by step
- Drag your tracks into the key and BPM finder; analysis runs in your browser and nothing is uploaded.
- Review the results; confirm doubtful ones with the key wheel and the listen buttons on the key pages.
- Save the tagged copies one by one, as a ZIP or (in Chrome/Edge) straight into a folder.
- Add the new files to your DJ software, or refresh the tags with Reload Tag.
If your library has WAV files and you want tags, you can convert them to AIFF or FLAC first; between lossless formats the audio stays bit-for-bit identical.