How to check BPM and key
Follow a practice clip from input to a checked result, then learn what to do when the tempo or key needs another look.
Use the audio analyzer alongside this guide. Returning to the analyzer loads a new page, so choose your audio again. Keep this guide open in a separate tab if you want to follow the steps while listening.
Try a 120 BPM, A minor practice clip
This original 32-second clip was generated for this exercise. Its reference tempo and key come from the synthesis settings: 120 BPM · A minor · 8A. It is not a real song or evidence of accuracy on other music. You may freely use the clip.
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Choose the input. Download the teaching WAV (1.41 MB), then open the audio analyzer and use Choose audio to open the saved file. Analysis runs locally; you do not need to upload it.
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Compare the candidate with the reference. This version returned 120 BPM, A minor, and 8A in our Chrome check. Press Play audio and count the steady pulse. The numerical match shows this exercise worked, not that every future detection will be right.
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Practice checking a half-tempo reading. Choose Half: the result becomes 60 BPM while the audio keeps playing at its original speed. Count every other beat to hear that interpretation. Choose Double to return to the clip's 120 BPM reference. No correction submission is needed for this exercise.
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Copy the checked values. Choose Copy result. After the Half/Double exercise, the copied text identifies the result as adjusted:
120 BPM · A minor · Camelot 8A (manually adjusted)Before any changes, the same values are labeled “algorithm candidates.” To undo practice changes, open Correct result and choose Restore detected values.
When the result needs a second look
70 or 140 BPM: which pulse are you counting?
Play a steady passage and count “1, 2, 3, 4” with the pulse you want to use in your project. Try counting twice as often, then half as often. A 70 BPM pulse is about 0.86 seconds apart; 140 BPM is about 0.43 seconds apart. Both readings can describe different levels of the same rhythm.
In the audio analyzer, choose Check tempo by tapping beside your BPM result to check your count. Choose Half or Double if that value fits. The inline tap check keeps your file; applying a tapped value requires Apply to current audio. These controls change the result, not playback speed. Check the choice against a metronome in your music software before arranging a long track.
Unclear key: find pitched evidence first
Use the playback slider to listen where bass, chords, or melody are present. Compare with the notes and chords in the source project, a reliable reference for this exact recording, or a keyboard. Listen for the tonal center and whether the harmony supports major or minor; one matching note is not enough.
The slider changes what you hear, not which part is analyzed. To analyze a passage separately, export it as an MP3 or WAV of at least four seconds in your own editor, then choose that file in the audio analyzer. If the evidence is still ambiguous, keep the key unclear and use the tempo on its own. To remove an unsupported key, open Correct result, select Unclear, and save; Camelot is removed too. Saving shares the correction details and audio identifier as explained beside the save button.
A song changes tempo or key halfway through
Listen near the start, middle, and end. A single BPM or key cannot describe every section of a changing song. For files longer than 90 seconds, this tool samples 30-second sections from the beginning, middle, and end; it does not build a tempo map or mark key changes on the waveform.
Export the sections you need in your audio editor and analyze them separately. Keep a note of which section each copied result describes. For a live performance with changing timing, work with your editor's tempo mapping or manual alignment rather than forcing the entire recording to match one estimate.
Take a checked result into your project
Check more than the first few beats
Set your project to the candidate BPM, align the audio's first downbeat, and compare it with the metronome over several phrases. A constant offset suggests a start-position issue. A steadily growing offset suggests a tempo mismatch; drift that begins at one section can signal a timing change there. Check the recording before adjusting the number again.
For example, in Ableton Live 12, turn the clip's Warp switch off to compare its original timing against the project tempo. With Warp on, the clip can follow the project tempo, so alignment alone would not verify its original BPM. See Ableton's warping guide.
Use Key and Camelot as references
An A minor result is shown as 8A in Camelot. These are two names for the same selected key, not two independent checks. Use them to choose something to audition, then listen to the overlapping bass, melody, and chords. Matching codes do not guarantee that two recordings will work together.
Copy tempo, Copy key, and Copy Camelot copy individual values. Copy result includes whether the values are algorithm candidates or manually adjusted. None of these actions changes the source file, its tags, pitch, or tempo.