Beat grid editor
Estimate the tempo and beat positions of a recording, correct the tempo or first beat yourself, then export the beat grid as CSV and a MIDI tempo map.
Accepted files: .wav,.mp3,.m4a,.aac,.flac,.ogg,.oga,.opus,.webm,audio/*. Choose one file. Up to 256 MiB in total.
One file up to 256 MiB, 10 minutes, 8 channels and 60 million samples, with at least 2 seconds of audio. Search range 30 to 300 BPM for the lowest and 40 to 400 BPM for the highest tempo, the lowest below the highest. Corrected tempo 0 (use the estimate) or 30 to 400 BPM, corrected first beat -1 (use the estimate) or 0 to 600 seconds, 1 to 12 beats per bar and at most 200,000 beats. WAV is read directly with every channel and sample intact. MP3, M4A, AAC, FLAC, OGG, Opus and WebM are decoded by your browser and resampled to 48 kHz first, so decoding support depends on the browser. Files are decoded and measured on your device and are never uploaded. Downloads: JSON report, CSV of beats and a MIDI tempo map. Run once for the estimate, then correct the tempo or first beat below. Up to 1,000,000 characters. Review the settings before running.
Your result
How to use Beat grid editor
- Choose one audio file from your device.
- Set the tempo range to search and the beats per bar.
- Run the estimate and compare it with what you hear, including the half and double tempo alternatives.
- If it is off, enter the corrected tempo or first beat time and run again.
- Download the beat CSV and the MIDI tempo map.
Useful next steps
How the estimate works
The tool builds an onset curve from the spectral flux of 23 millisecond frames, finds the strongest repeating period with an autocorrelation that slightly favours tempos near 120 BPM, refines it with a comb search and aligns the beat phase to the onsets. The beat position with the strongest accumulated onsets is taken as beat 1 of each bar. Half and double tempos are listed because they are the most common mistake.
Correcting the grid
The result is an estimate. Enter a corrected tempo, a corrected first beat time, or both, and run again: the grid is then rebuilt exactly from your values with a constant tempo, starting on beat 1 at your first beat. The report keeps the original estimate next to the values used.
What is exported
The CSV lists every beat with its time in seconds, bar and beat number. The MIDI file is a type 0 tempo map with one tempo event and one wood block click per beat (high on beat 1), so a music program can follow the recording. Tempo changes within the recording are not detected; a constant grid drifts on music that speeds up or slows down.