BPM Detector for Audio Files
Choose an audio file and the tool estimates its BPM (beats per minute). It finds where sounds start (onsets) and measures how regularly they repeat to work out the beat interval. The result is an estimate, so to check it by ear, tap along with the BPM Tap Tempo tool, or turn the BPM into delay times with the BPM Delay Calculator. Everything runs in your browser, so your file is never uploaded.
🔒 Runs in your browser · Your data is never sent to a server
You can also drag and drop a file here
Analyzing…
Detected tempo
BPM
Confidence (rough guide):
This is only an estimate. Depending on the track it may return half or double the tempo, or be off by a few BPM.
How to use
- Choose an audio file (drag and drop also works).
- Once it loads, the file is analyzed automatically and "Detected tempo" shows the BPM with a rough confidence level.
- Compare the half and double candidates, pick the one that fits the song, and note it down with "Copy BPM".
Notes
- The result is an estimate and its accuracy is not guaranteed. Tracks with a clear beat, such as drum-driven music, usually work well; ambient music, rubato playing, frequent meter changes and live recordings are more likely to be off.
- The tool can return half or double the real tempo (for example 140 BPM for a 70 BPM song). Half and double candidates are shown next to the result so you can pick the one that fits the song.
- The search range is 60 to 200 BPM. Slower or faster songs are reported as a multiple or fraction that falls inside this range.
- If the tempo changes during the song, only the single most prominent period is returned. For long tracks, only about 90 seconds from the middle are analyzed.
- Any format your browser can decode works (MP3, WAV, M4A, OGG and so on). The limits are 20 minutes of audio and a 200 MB file.
- All processing happens in your browser; the file you choose is never sent to a server.
Glossary
BPM
Beats per minute, the unit of tempo. At 120 BPM each beat lasts 0.5 seconds.
Onset
The moment a sound begins, such as a drum hit or a guitar pick, where the volume rises sharply.
Autocorrelation
How well a signal matches a shifted copy of itself. If something repeats at a steady interval, the match is strongest at that interval, which is how the beat period is estimated.
Half / double tempo
Counting the beat at half or twice the real tempo. It is the most common mistake in BPM detection and comes from different ways of counting the rhythm.
FAQ
How accurate is the detected BPM?
Treat it as a rough guide. Tracks with a clear beat, such as drum-driven music, are often within 1 to 2 BPM, but ambient music, rubato playing and live recordings are more likely to be off. For anything important, double-check by ear with a tap tempo tool.
Why does it show half or double the real BPM?
The tool relies only on how regularly the beats repeat, so it cannot always tell whether you would count one beat or two, or quarter notes or eighth notes. Half and double candidates are shown next to the result so you can pick the one that fits the song.
What happens with songs whose tempo changes?
It returns the single most prominent period over the whole track (about 90 seconds from the middle for long ones). For songs that change tempo or speed up and slow down gradually, you will not get an exact BPM for each section.
What BPM range can it detect?
It searches from 60 to 200 BPM. Slower or faster songs may be reported as a multiple or fraction that falls in that range, for example 100 BPM for a 50 BPM song.
Can it analyze very short or silent audio?
No. Finding a repeating period needs some length, so audio shorter than 4 seconds and nearly silent files show a "could not detect" message.
Share this page