Audio Key Finder
Key one track at a time is slow when you're prepping a set. Drop a whole folder and get one table — key, Camelot code and BPM for every file, analysed on your own machine.
Powered by the Web Audio API. Your files never leave your device.
Who needs batch key detection
DJs keying a whole crate
New tracks arrive faster than anyone keys them one at a time. Dropping a folder and walking away turns an evening of clicking into one pass, and the table sorts into a set order.
Music librarians and catalogers
Key and tempo are the two fields most music libraries need and most files lack. Batch analysis fills a metadata gap across a collection rather than one track at a time.
Playlist curators
A playlist that flows harmonically holds attention longer than one that jars every third track. Seeing every Camelot code at once lets you order the list deliberately.
Producers organising sample packs
A pack of loops with no key labels is a pack you won't use. Running the folder once and noting the keys turns unusable downloads into a library you can actually pull from.
How batch key detection works
1. Drop in your crate
Select or drag up to 25 audio files at once. Nothing is uploaded — each file is decoded and analysed locally by your browser, one after another.
2. Each file gets two passes
A chromagram pass matches the note distribution against all 24 keys, and a low-band pass measures kick spacing for tempo. Files that fail to decode are marked failed, not reported as keyless.
3. Read the whole set at once
Results fill in row by row as they finish. Sort your set by Camelot number to plan transitions, or by BPM to group tracks that beatmatch without stretching.
Audio key finder FAQ
Can I find the key of multiple songs at once?
Yes — that's what this page is for. Drop up to 25 files and every one gets a key, a Camelot code and a BPM in a single table. The single-file Key Finder is better when you just want one answer with alternates and the full Camelot reference.
Why does it process files one at a time?
The analysis is CPU-bound and runs on your machine, in the browser's main thread. Firing all 25 at once wouldn't make them finish sooner — it would just make the page unresponsive and deliver every row late. Sequential processing keeps the table updating as it goes.
How do I use Camelot codes to build a set?
Tracks that share a Camelot number, or sit one number apart on the wheel, mix without their melodies clashing. Moving between the A and B of the same number is a major-to-relative-minor switch, which also works. Sorting this table by code gives you the mixable neighbours at a glance.
What does 'failed' mean in the key column?
The file couldn't be decoded — a corrupt file, or a codec your browser doesn't support. It's shown separately from 'no key' on purpose: no key means the analysis ran and found nothing tonal, while failed means the analysis never ran. Converting to MP3 or WAV usually fixes it.
Is there a file size or count limit?
25 files per batch, and files under roughly 25 MB each analyse comfortably. There's no account limit or upload quota because nothing is uploaded — the ceiling is just your browser's memory and how long you want to wait.
Are the results as accurate as single-file analysis?
Identical — it's the same detection running per file. The usual caveats apply to each row: the relative major or minor shares the same notes and Camelot number and is the common near-miss, and tempo is folded into 90-180 BPM so some rows may need halving or doubling.
Key your whole crate in one pass.
Drop 25 tracks, get one table of keys, Camelot codes and tempos.
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