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 practise with a metronome that follows the song, drift and all: a count-in, subdivisions, a loop that snaps to the bars and the speed from 50% to 150% without changing the pitch. Download the tempo map or the click track 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…
Play opens as soon as the click is ready.
Click on the off-beat?
Click settings
Tap on the 1 while the song plays. The bars and the accent follow from there, and if the click was on the off-beat there, it moves onto the beat.
Keys: Space plays, C the click, B beat 1, L the loop, the arrows a beat (with Shift a bar), minus and plus the speed.
This browser cannot keep the song between pages. Choose it again in the console; your analysis stays here.
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.
Want a click with no song at all? The online metronome has accents, subdivisions, tap BPM and a speed trainer.
Now split it into stems and practise the part
Already have a song open in the console? Choose Key & BPM beneath its title to explore the same song here, then return to practice. Your stem mix and saved loops stay in place.
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. The free speed and key player slows the whole song down without changing the pitch, or moves it into a key that suits your voice; Pro does the same on the stems.
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. A neural network trained on thousands of songs with every beat marked by hand places the beats and the bar lines: Beat This!, from the Institute of Computational Perception at JKU Linz (Foscarin, Schlüter and Widmer, 2024), in its small version, released under the MIT licence. It runs in your browser like the rest of the finder, so the first song downloads it once. A computer quick enough runs three trainings of it and averages them, which keeps the click on the beat more surely. A stretch that sits on a straight grid, a song played to a click, snaps to that grid, so the click and the tempo map stay exact; a band that drifts keeps its own timing. The bar lines show where they stand out clearly. A device too slow for the network gets the finder’s own tracker instead: dynamic programming (Ellis, 2007), which keeps the chain of beats that lands on the most onsets while holding the local tempo.
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.
The beats and bar lines come from the beat network, measured on real recordings. On 49 finished masters of Dan Murtagh’s own songs (rock, pop and progressive), checked beat by beat against the larger Beat This! model, the click sat off the beat for two bars or more in 1.5% of the song time with the three networks a fast computer averages, and 2.4% with the one a phone runs; the finder’s earlier tracker did so in 8.6%. Bar lines showed on 33 of the 49 songs, and 9 in 10 of them fell where the larger model put them. On GTZAN, 1,000 clips in ten genres marked by hand that the network never trained on, its authors measured a beat F1 of 88.8 and a bar line F1 of 77.2. The last two rows below are the finder’s built-in tracker, used where the network cannot run.
| 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, built-in tracker | 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, built-in tracker | 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 and the key on 142 of 144 chord progressions. Its beats come from a neural beat tracker: on 49 real masters, checked against a larger model, the click sat off the beat for two bars or more in only 1.5% to 2.4% of the song time. 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.
Is there a metronome that follows the song?
Yes. Press play: the click is on, and it ticks on the song’s own beats, so it stays with a band that speeds up or drifts. Loop a few bars, snapped to the bar lines, and under Click settings choose a woodblock, rim, hi-hat or beep, subdivide into eighths, triplets or sixteenths, or add a one or two bar count-in. The accent falls on beat 1 where the bars are clear; elsewhere, tap beat 1 while it plays. The click follows the ÷2 and ×2 buttons.
What if the click is on the off-beat?
Tap beat 1 on the real 1 while the song plays. Where the tracking slipped onto the off-beat, the finder moves that stretch of beats back onto the beat, from where it slipped to where it came back, and counts the bars from your tap. Counted at ÷2, the tap switches to the other half of the beats; at ×2 it sets the bars only. Move beat 1 shifts the bars a beat earlier or later, and Undo takes back the last fix.
Can I slow the song down to practise?
Yes, free. The speed control plays the song from 50% to 150% without changing its pitch, and the click slows down with it, so you can learn a fast part at 75% and build back up to full speed.
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.
Can I download the click as an audio track?
Yes. Download click track (WAV) saves the click on its own from 0:00, the length of the song, with your sound, bars and subdivision. Put it at the start of a session beside the song in Pro Tools, Logic Pro, Cubase or Reaper, or send it to a drummer’s in-ear mix.
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 Separate instruments to practise, your browser holds the song until the splitter opens and takes it, then you choose the instruments and start the upload in the console.
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 analyses and plays the full song, including songs longer than 10 minutes. Longer songs may take more time to analyse.
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 song into your range without changing its speed, free in your browser.
Slow down a song without changing pitch
Learn fast passages at a comfortable speed in the original key, free in your browser.
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.
Online metronome
Accents, subdivisions, tap BPM and a speed trainer, free in your browser.
Written by Dan Murtagh, mixing engineer and audio educator. Updated 4 October 2026.