Your DJ software already finds the BPM and key of every track it analyses: rekordbox, Serato DJ Pro, Traktor Pro and the free Mixxx all do, and each can show keys in a notation built for harmonic mixing. Add Mixed In Key if you want a dedicated key analyser that also rates energy and writes its results and cue points into your files for any software, and use SongBPM to look up a song you don't own.
Start with your DJ software
Each of these analyses BPM and key when it analyses a track. The settings that matter are which notation it shows and whether it writes the key into the file, so other software can read it.
| Software | Where the settings are | Key notations |
|---|---|---|
| rekordbox 7 | Preferences > Analysis > Track Analysis; Preferences > View > Display Type > Key display format | Classic (such as Abm) or Alphanumeric (such as 1A) |
| Serato DJ Pro | Analysis Settings in offline mode; SETUP > Library + Display | Camelot, Open Key, musical, or the key already in the file |
| Traktor Pro | Preferences > Analyze Options > Musical Key | Musical, Musical (all sharps) or Open Key |
| Mixxx 2.5 | Preferences > Key Detection | Chosen under Key Notation |
rekordbox
In the rekordbox 7.2.18 manual, the [Track Analysis Setting] boxes under Preferences > [Analysis] > [Track Analysis] choose what is analysed: [BPM / Grid], [KEY], [Phrase] and [Vocal]. [Track Analysis Mode] is [Normal] for tracks with a steady tempo, where you also set the [BPM Range], or [Dynamic] for tracks whose tempo changes. Under [Key Analysis], [Write the value to the ID3 tag] stores the key in the file. The key column can highlight the tracks whose keys suit the track on the selected deck, which rekordbox calls Traffic Light, and the track filter can narrow a list to the key of the track on the master deck. See what rekordbox is and how to organise music in rekordbox.
Serato DJ Pro
Serato analyses key when "Set Key" is on in the Analysis Settings drop-down and writes it to the track, per Serato support. The display format is in the Library + Display tab of the SETUP screen, where Serato offers Camelot, Open Key, musical notation or the original tag. See what Serato DJ is.
Traktor Pro
The Traktor Pro manual puts both settings on the Analyze Options page. BPM Range has an Automatic setting that, Native Instruments says, helps it read Drum and Bass at around 170 BPM rather than 85. Under Musical Key, "Displayed in Traktor" sets the notation in the Key column and "Written to File Tags" sets the one saved into the file. Traktor has no Camelot option; its Open Key notation uses different codes. See what Traktor DJ is.
Mixxx (free)
Mixxx is free, with no paid version, and runs on Windows, macOS and Linux; 2.5.6 was the stable release on 12 October 2026. Its Key Detection preferences include Enable Fast Analysis, which works out the key from the first minute of a track, and Key Notation. Since Mixxx 2.3 it has used the KeyFinder key detection library, whose upkeep its author handed to the Mixxx team in 2020.
When a separate key finder helps
Mixed In Key 11
Mixed In Key analyses key, BPM, an Energy Level from 1 to 10 and up to eight cue points per track. It writes key and energy into your files' tags, so the results show up in Serato, Traktor, VirtualDJ and on Pioneer DJ players, and it exports cue points to Traktor, Serato and rekordbox. It reads MP3, WAV, AIFF, Apple Lossless, OGG and FLAC, and has a built-in piano for checking a result by ear. Mixed In Key 11 Pro adds suggestions for tracks that mix or mash up well. The shop sells both as downloads, with prices shown there.
It is worth adding if you use more than one DJ program and want the same keys in all of them, or if you want energy ratings to plan sets. Mixed In Key says version 11 is more accurate than any other software; we haven't seen an independent test of version 11 that checks it.
To keep its keys, stop your DJ software overwriting them: turn off "Set Key" in Serato's Analysis Settings and set the key display to the original tag, per Serato support, or in rekordbox choose [Display key information on the database] under [Key display format].
KeyFinder DJ (free, Mac)
The original free KeyFinder is now KeyFinder DJ on the Mac App Store: free, for macOS 10.15 or later, at version 3.0.10 from July 2025. Its author describes it as deliberately narrow, with no library management or player, and on Windows or Linux points people to Mixxx, which uses the same algorithm.
Looking up a song you don't own
SongBPM lists the BPM and key of songs by search and credits its song data to Spotify. It suits planning a request list or checking a song before you buy it. The figures belong to the version listed, so analyse your own file once you have it: an extended mix or edit can differ.
Reading the results
Camelot and Alphanumeric codes
Mixed In Key's guide gives each key a number and a letter: A for minor keys, B for major. From any code there are four compatible moves: stay on the same code, go one number up or down (8A to 9A or 7A), or keep the number and switch the letter (8A to 8B). rekordbox's Alphanumeric display uses codes of the same 1A to 12B form. If you use more than one program, pick one notation for all of them. Mixing in key covers how to use the matches in a set.
Half and double tempo
One error to look for is a BPM at half or double the real tempo; the Traktor manual's example is Drum and Bass read at 85 instead of 170. Narrow the BPM range in rekordbox's Normal mode, or use Traktor's Automatic setting, then re-analyse. The beatgrid is built on that BPM, so fix it before you set cues, and see how to beatmatch for matching tempos by ear.
How this page is made
Every setting and feature named here comes from the maker's own manual, help page or product page, linked above and read on 12 October 2026. We haven't run our own accuracy comparison of these analysers, and the accuracy figures on the old version of this page have been removed because no source for them could be found. The methodology explains how the site works.
