BPM Detector Detect the tempo (BPM) of any audio or music file.

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BPM Detector

Detect the tempo (BPM) of any audio or music file.

Upload Audio

Drop your music or audio file or click to browse.

Detect BPM

Click Detect to analyze the tempo of your audio.

View Results

See the detected BPM, confidence score, and tempo classification.

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What Is BPM Detector?

The BPM Detector analyzes audio files to detect the tempo in beats per minute (BPM). Drop any music file and the tool will examine the rhythmic content to determine the exact BPM. This uses beat detection algorithms implemented with the Web Audio API, processing audio entirely in the browser. The detector works best with rhythmic music but can also process spoken word and ambient audio. Results include the detected BPM value, confidence level, and tempo classification (e.g., Allegro, Moderato).

Why Use BPM Detector?

Accurate BPM detection using multiple analysis algorithms
Works with any audio format (MP3, WAV, OGG, etc.)
Shows confidence level and tempo classification
Completely browser-based — no uploads needed

Common Use Cases

DJing

Determine track BPMs for beat-matching and playlist organization.

Music Production

Find the tempo of samples, loops, and reference tracks.

Exercise Playlists

Sort music by BPM for running, cycling, or workout playlists.

Music Theory

Analyze and study the tempo of different musical pieces and genres.

Technical Guide

The BPM detection uses a multi-stage algorithm. First, the audio is decoded into an AudioBuffer and mixed to mono. A lowpass filter emphasizes bass frequencies where beats are most prominent. The filtered signal undergoes onset detection: the audio is divided into windows, and the spectral flux (change in energy between consecutive frames) is calculated. Peaks in the onset detection function correspond to beats. The inter-onset intervals are then analyzed using autocorrelation to find the most common periodicity, which gives the BPM. The autocorrelation function R(τ) = Σ x(n) * x(n+τ) reveals the dominant periodicity. The BPM is calculated as 60 / peakPeriod. Multiple candidate tempos are evaluated and the most statistically consistent one is selected. The confidence score reflects how clearly periodic the rhythm is.

Tips & Best Practices

1
Works best with music that has a clear, steady beat
2
Rock, pop, electronic, and hip-hop typically give the most accurate results
3
Classical music and jazz with tempo changes may give less reliable results
4
If the detected BPM seems half or double the actual tempo, it's a common octave error — just multiply or divide by 2

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Frequently Asked Questions

Q How accurate is the BPM detection?

For music with a clear, steady beat, accuracy is typically within ±1 BPM. Music with varying tempo or no clear rhythm gives less reliable results.

Q What is BPM?

BPM (Beats Per Minute) measures musical tempo. 120 BPM means 120 beats occur in one minute. Higher BPM = faster music.

Q Why does it sometimes show half/double the expected BPM?

This is a common "octave error" in BPM detection. The algorithm may lock onto half-beats or every-other-beat. Simply multiply or divide by 2.

Q Does it work with vocal-only tracks?

The detector is optimized for rhythmic music. Spoken word or a cappella recordings may not produce accurate BPM results.

Q Is my music uploaded?

No. All BPM analysis happens locally in your browser. Your files never leave your device.

About This Tool

BPM Detector is a free online tool by FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration or installation required.