Free · In your browser · Never uploaded
Key & BPM Finder
Add a song below to find its key, relative key and Camelot number, and its tempo in BPM with half-time and double-time readings. Then play it on a waveform with its beat grid and a click, and download the tempo map for your DAW. It is free, with a tap tempo pad to check the beat by ear.
Analysed on your device · never uploaded
Reading the file…
Now split it into stems and practise the part. Solo the bass, mute the drums or loop the bar you are learning.
Split a song freeTap tempo
No file handy, or want to check the beat by ear? Tap the pad in time with the music. On a computer, click it once and keep time on the space bar. Four taps give a reading and more taps steady it; a pause of a few seconds starts a new count.
Tap along to the beat.
Now split it into stems and practise the part
The key and the tempo tell you where the song sits. StemConsole lets you hear the part itself: it splits the song into vocals, drums, bass and everything else, so you can solo the bass line, mute the drums and play them yourself, or loop the bar you are learning. With Pro you can also slow it down without changing the pitch, or move it into a key that suits your voice.
How the key and BPM finder works
Tempo. The finder measures how sharply the sound rises in four frequency bands, from the kick drum to the hi-hats, about 90 times a second. It then finds the beat length that lines those rises up best across the whole song, leaning towards the tempos songs usually have. Measuring across the whole track pins the BPM to a fraction of a beat per minute. It also reads the song in 16-second stretches, so a tempo change or a live band’s drift shows up. In 6/8 and 12/8 it looks for the dotted quarter, the beat you tap your foot to.
Beats and bars. To place every beat it uses dynamic programming (Ellis, 2007): of all the chains of beats through the song, it keeps the one that lands on the most onsets while holding the local tempo, so the grid follows a tempo change or a live band’s drift. A song played to a click snaps to an exact grid. The first beat of a bar is where the kick drum and the chord changes land and the snare does not, and the bar lines show only when that holds across the song.
Key. It picks out the pitched notes, corrects for tuning so a song recorded a little sharp or flat still reads right, and folds them into the 12 note names. That note profile is compared with major and minor key profiles from music cognition research (Krumhansl and Kessler; Temperley), and the closest of the 24 keys wins. Confidence shows how far ahead of the runner-up it finished. It scores every few seconds of the song as well, so a key change shows with its time.
All of this runs in your browser with the Web Audio API. The audio never leaves your device, and playback uses your own file.
How accurate it is
Every change to the finder is tested against 260 generated signals with a known key and tempo: click tracks, drum loops in five styles, and chord progressions in all 24 keys with bass, melody and drums, some tuned up to 45 cents away from A440. Three-minute songs that lift key, change tempo, drift like a live band or sit in 3/4, 6/8 and 12/8 test the sections, the beats and the bars against their exact beat times.
| Test | Result |
|---|---|
| Tempo, 80 to 150 BPM | 157 of 159 within 0.1 BPM |
| Tempo, 60 to 180 BPM | 193 of 232 within 0.1 BPM; the other 39 read at exactly half or double time |
| Key, all 24 keys | 142 of 144 right; the other 2 read the relative key |
| Key lifts and tempo changes | 16 of 19 songs read right, each change within 2 seconds for a key and 4 for a tempo; 20 of 20 steady songs show no change |
| Beats | 98% of beats found within 70 milliseconds, and 97% of the beats marked are real ones, across 325 signals, counted with ÷2 or ×2 where they help |
| Bar lines | Marked on 87 of 325 signals with bar lines, with 91% of the bar lines marked on true ones and 96% of the true ones marked; the rest show the beats only |
Real recordings add what generated signals leave out, such as vocals, effects and dense mixes. A song that sits between a major key and its relative minor can read as either, so the relative key is always shown. A very slow or very fast groove can be counted at half or double time, so the ÷2 and ×2 buttons switch between them, and the beat grid, the click and the tempo map follow. A section can read that way on its own too, so a jump from 80 to 120 BPM can show as 160 to 120, or as 80 to 60.
Camelot wheel: keys for harmonic mixing
DJs write keys as Camelot numbers. Tracks with the same number, or one number apart with the same letter, mix without clashing. A is the minor key and B its relative major.
| Camelot | Minor (A) | Major (B) |
|---|---|---|
| 1 | G♯ minor | B major |
| 2 | E♭ minor | F♯ major |
| 3 | B♭ minor | D♭ major |
| 4 | F minor | A♭ major |
| 5 | C minor | E♭ major |
| 6 | G minor | B♭ major |
| 7 | D minor | F major |
| 8 | A minor | C major |
| 9 | E minor | G major |
| 10 | B minor | D major |
| 11 | F♯ minor | A major |
| 12 | C♯ minor | E major |
Frequently asked questions
How accurate is this key and BPM finder?
On generated test signals with a known answer, it read the tempo within 0.1 BPM on 157 of 159 between 80 and 150 BPM, the key on 142 of 144 chord progressions, and found 98% of beats within 70 milliseconds. Very slow or very fast grooves can read at half or double time, and a song between a major key and its relative minor can read as the relative key, so both are shown.
What does BPM mean?
Beats per minute: how many beats, the pulse you tap your foot to, pass in one minute. 60 BPM is one beat a second and 120 BPM is two. It lets you set a metronome, a drum machine or a DAW project to the song, or match two tracks in a DJ mix.
What does the key of a song mean?
The key is the note a song feels at home on, plus the scale built on it, major or minor. A song in A minor keeps returning to A and mostly uses the notes of the A minor scale. It tells you which scale to solo in, which chords will fit, and whether two songs will blend in a mix.
What are half-time and double-time?
Many grooves can be counted at two speeds: a drum and bass track at 174 BPM also feels like 87, and a slow hip-hop beat at 70 can feel like 140. If the number feels twice too fast or too slow, press ÷2 or ×2. The measurement stays exact; only the counting changes, and the beat grid, the click and the tempo map count the same way.
What if the song changes key or tempo?
The finder also reads the song in sections. It names the key the song spends longest in and the tempo that fits the whole song best, and shows a clear change with its time, such as a lift to D♭ major for the last chorus or a faster final section. Keys a fifth or a whole tone apart share most of their notes, so a move between them, like a chorus that leans on the fifth chord, can read as one key. A band playing without a click shows its tempo range.
Does it work for songs in 6/8 or 12/8?
Yes. The finder counts the beat you tap your foot to, which in 6/8 and 12/8 is the dotted quarter. In a slow song, or one with loud eighth notes, it can count the eighth notes (three to a beat) or pairs of them instead; tap along below to count the beat you feel.
Can I hear the beat grid against the song?
Yes. Press play to hear your file with its waveform, key and tempo sections and beat grid, and switch on the click for a tick on every beat, accented on the first beat of each bar when the bars are clear. The click follows the ÷2 and ×2 buttons.
Can I use the tempo map in my DAW?
Yes. Download tempo map (MIDI) saves a MIDI file with a tempo change on each beat that moves, the time signature when the bars are clear, and the key. Import its tempo into Pro Tools, Logic Pro, Cubase or Reaper with the song at the start of the session, and the grid lines up with the song’s beats.
What is a Camelot number?
Camelot is the DJ shorthand for the 24 keys: numbers 1 to 12 around the circle of fifths, A for minor and B for major. Keys with the same number, or one number apart with the same letter, mix without clashing, so 8A (A minor) sits well next to 7A, 9A and 8B.
Is my song uploaded?
No. Your browser decodes and analyses the file on your device, and the audio never leaves it. Nothing is kept either: close the tab and it is gone. If you choose Split this song into stems, your browser holds the song until the splitter opens and takes it, then the splitter uploads it, as it does any song you split.
Which audio files work?
MP3, WAV, FLAC and AAC (.m4a) files work in any current browser, and OGG in most. Files can be up to 100 MB (40 MB for M4A and OGG). The finder reads the first 10 minutes, or the start of a very long MP3, which covers almost every song.
Does it work on a phone?
Yes, in the mobile browser with nothing to install. Choose a song from your phone’s files and it reads the key and tempo in a few seconds. The tap tempo pad works with a finger too.
Is it free?
Yes, with no sign-up and no limit. It is part of StemConsole, which splits songs into stems so you can practise the part; the first split needs no account either.
Related guides and tools
Change the key of a song
Move a backing track into your range without changing its speed (Pro).
Slow down a song without changing pitch
Learn fast passages at a comfortable speed in the original key (Pro).
Loop a section of a song
Repeat a phrase until it sits under your fingers. Basic looping is free.
Learn a song by ear
Solo the part, loop the phrase and work out the notes.
Create a backing track from any song
Set each stem’s level, then bounce the mix: MP3 free, WAV with Pro.
Practise guitar with a backing track
Mute the guitar and play over the real band.
Written by Dan Murtagh, mixing engineer and audio educator. Updated 27 September 2026.