Free · No sign-up · Runs in your browser

Key & BPM Finder

The two numbers you need before you mix or remix a track, from a single upload — musical key with its Camelot code, and tempo in BPM.

Drop audio here

or click to upload

MP3, WAV, FLAC, OGG, M4A · under 25 MB works best

What is a key and BPM finder?

A key and BPM finder is a tool that reads the two numbers that define how a track combines with other tracks: its musical key — which of the 24 major and minor keys its melody and harmony sit in — and its tempo in beats per minute. DJs know the pair as the basis of harmonic mixing; producers need it before pitching a sample or an a cappella into a project.

The key is usually reported together with its Camelot code, a wheel notation that turns key compatibility into simple arithmetic: tracks one step apart on the wheel blend without clashing, and the relative major and minor share a number. That's why a key finder built for mixing always shows the Camelot code next to the note name.

This finder runs both detections on the same upload, entirely in your browser: a chromagram pass matches the track's note-energy profile against all 24 keys, while a separate low-band pass tracks the kick drum for tempo. Nothing is sent to a server, which is also why it needs no account and has no usage limit.

Key & BPM finder features

Key and tempo from one upload

One file in, both numbers out — the key with its Camelot code and the BPM, detected in separate passes over the same decoded audio.

Camelot codes for harmonic mixing

Every key result carries its Camelot wheel position, so planning a clash-free transition is one step of wheel arithmetic instead of music theory.

Runner-up candidates listed

The relative major/minor and half/double tempo are the classic near-misses, so the likely alternates are always listed under the main result.

100% in your browser

Decoding and analysis run on your own device with the Web Audio API. The file is never uploaded, which is why there's no sign-up and no size quota.

Five audio formats

MP3, WAV, FLAC, OGG and M4A all work — anything your browser can decode. Files under about 25 MB analyse fastest.

Free and unlimited

No credits, no watermarks, no daily cap. Analyse a whole crate one track at a time, or use the batch Audio Key Finder for 25 at once.

Who needs key and BPM together

DJs preparing a set

Beatmatching needs tempo and avoiding key clash needs the key — you can't plan a transition with only one of them. Getting both from a single upload is the difference between prepping a set in an evening and prepping it over a week.

Remixers and bootleg makers

Before you can drop an a cappella over a new instrumental you need to know how far each has to move, in both tempo and pitch. Those two numbers decide whether the idea works at all or needs a different pairing.

Sample flippers

A sample pitched to fit your project changes tempo too, and vice versa. Knowing where the source actually sits lets you calculate the move instead of nudging by ear until it sounds close.

Cover and karaoke musicians

Learning a song means knowing what key to play it in and how fast it goes. Both are on the sheet you never got, so reading them off the recording is usually the fastest route to a first rehearsal.

How it works

1. Drop in a track
MP3, WAV, FLAC, OGG or M4A. The file is decoded and analysed on your own device with the Web Audio API — nothing is uploaded to a server.
2. Two passes, one file
A chromagram pass reads which pitch classes carry the energy for key detection, while a separate low-band pass tracks the kick drum for tempo. They run together on the same decoded audio.
3. Read key + tempo
You get the key with its Camelot code for harmonic mixing, and the BPM. Runner-up candidates are listed underneath, because a wrong octave or a relative key is the usual failure mode.

Key and BPM finder FAQ

How do I find the key and BPM of a song?

Upload the audio file here. The tool builds a note-energy profile across the track and matches it against all 24 major and minor keys, and separately measures the spacing between kick-drum hits to derive tempo. Both results appear together, with alternates listed.

Why do I need both key and BPM?

To beatmatch, you need the tempo; to avoid clashing melodies, you need the key. DJs use both to plan transitions — tracks within a few BPM of each other and one step apart on the Camelot wheel blend cleanly. Producers need them to pitch samples correctly into a project.

Is my audio uploaded anywhere?

No. Detection runs entirely in your browser using the Web Audio API. Your file is decoded and analysed on your device and never leaves it, which is also why there's no sign-up and no file-size account limit.

Why is the BPM half or double what I expected?

Tempo detection folds results into a 90-180 BPM range to collapse octave errors, so a 75 BPM hip-hop track can read as 150 and a 170 BPM drum-and-bass track as 85. If the number feels wrong, halve or double it — the alternates list usually contains the right one.

What if the key is wrong?

The most common miss is the relative major or minor, which shares the same seven notes and the same Camelot number — musically it's a near-miss, not a failure. Tracks that modulate, are atonal, or are mostly percussion are genuinely hard. Treat the result as a strong starting point and trust your ear.

What audio formats work?

Anything your browser can decode: MP3, WAV, FLAC, AIFF, OGG and M4A. Files under about 25 MB work best. Key uses the first 60 seconds and tempo the first 90, which is plenty for both to lock on.