Detect beats per minute, tap tempo, find musical key, and analyze your audio in real time. Powered by Web Audio API with waveform display, chromagram, and metronome built in.
Supports MP3, WAV, OGG, FLAC, AAC, M4A
Click start to detect BPM from your microphone. Works great for live music, DJing, or playing along.
Analyzes chromagram to detect musical key
From DJs and producers to music educators and podcasters β our BPM tool covers every use case.
Advanced onset detection algorithm analyzes your audio file and calculates the exact BPM with high accuracy within seconds.
Tap along to any song playing and instantly see the BPM. Fine-tune with the slider and save to your history for later reference.
Detect BPM in real-time from your microphone. Perfect for live performances, practicing instruments, or analyzing vinyl records.
Chromagram-based key detection identifies the root note and mode (major/minor) of any audio file with pitch class analysis.
Web Audio API powered metronome with adjustable BPM, time signatures (4/4, 3/4, 6/8, 5/4, 7/8), accent control, and multiple sounds.
Visual waveform display with detected beat marker overlay and frequency spectrum analysis for deep audio insight.
All BPM detections and tap tempo sessions are saved in your session history for easy comparison and reference.
Instantly calculate half-time (Γ·2) or double-time (Γ2) BPM values with a single click β essential for DJs and remixers.
Audio never leaves your device. All analysis runs locally in your browser using the Web Audio API. Completely private.
Tap the spacebar or screen along to your music, upload an audio file, or enable your microphone for live detection.
Our Web Audio API engine detects beat onsets, calculates inter-beat intervals, and determines the precise BPM in real time.
View BPM, musical key, time signature, waveform, beat markers, and chromagram. Save results to your session history.
Apply the detected BPM to the built-in metronome. Practice with the beat, change time signatures, and adjust accent patterns.
A BPM detector online is a web-based tool that measures the tempo of music in beats per minute (BPM). Whether you're a DJ preparing a seamless mix, a musician trying to match a backing track, or a producer analyzing reference tracks, knowing the exact tempo is essential. Our free tool eliminates the guesswork.
BPM stands for beats per minute β the standard measure of musical tempo. A track at 120 BPM has two beats per second, which is typical for house and pop music. A track at 140 BPM is common in techno and drum & bass. Jazz ballads often sit around 60β80 BPM, while drum & bass can exceed 170 BPM.
Our BPM finder online uses the Web Audio API to analyze audio data. It employs onset detection β identifying transient energy peaks in the audio signal β and calculates the statistical average of inter-onset intervals to produce a highly accurate BPM reading. The key finder uses chromagram analysis, measuring the energy distribution across 12 pitch classes (C, C#, D, D#, E, F, F#, G, G#, A, A#, B) to determine the tonal center.
Best practices: For the most accurate tap tempo readings, tap at least 8β16 times to allow the algorithm to average out timing inconsistencies. For file-based detection, 30+ seconds of audio with clear beats gives the best results. When finding the musical key, use recordings without heavy reverb or distortion for cleaner chromagram data. The half-time feature is invaluable when your music feels too fast β simply divide by two to find the underlying groove.
Common use cases include DJ set preparation and beatmatching, music production for finding tempo of samples, fitness instructors building workout playlists, music educators teaching rhythm, and remixers matching original track tempo to new arrangements. Our online BPM counter handles all of these without any software installation.
The file-based detector typically achieves Β±1 BPM accuracy on music with clear rhythmic patterns. Accuracy is highest with electronic music, drums, and percussive tracks. Complex jazz or classical music with rubato may show slight variations. Tap tempo accuracy improves with more taps β aim for 10+ taps.
Tap tempo is a manual BPM measurement method. Simply tap the on-screen button or press your spacebar in sync with the beat of the music. After 4β8 taps, the tool calculates the average interval between taps and displays the BPM. Reset any time and tap again for a fresh calculation.
Half-time means the tempo divided by two. If a track is at 140 BPM, half-time is 70 BPM. Double-time is the tempo multiplied by two (140 BPM β 280 BPM). These are useful for DJing, remixing, or practicing to a slower or faster groove while keeping the same musical feel.
Yes. The Key Finder tab uses chromagram analysis to detect the most likely root note and mode (major or minor) of your audio file. While no automated tool achieves 100% accuracy on all music, our chromagram approach is highly reliable for common tonal music.
Yes. When you enable microphone input, the tool continuously analyzes audio from your microphone using the Web Audio API and updates the BPM reading in real time. This works great for live drums, instruments played in the room, or music from a speaker.
No. All audio analysis happens entirely within your browser. Your audio files are processed locally using the Web Audio API and are never sent to any server. Your music and microphone audio remain 100% private on your device.
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