Find the BPM and key of a song
Drop a song to estimate its BPM (beats per minute) and key, with no tapping along. Use it to match songs in a DJ mix, set a metronome for practice or check the key of a song you are covering. You can analyze several songs at once.
How to use
- 1
Add songs
Drop the songs you want to check. You can analyze several at once.
- 2
Run
The whole song is analyzed to estimate its BPM and key.
- 3
Check the result
The BPM, key, Camelot code and other key candidates are shown. You can also save the result as JSON.
How BPM and key are estimated, and how accurate they are
The BPM is found from how the strength of note onsets (beats) changes over time, searching for its period with autocorrelation. It covers 60–200 BPM and favors common tempos (around 120), so it can mistake the tempo for double or half (for example 70 and 140).
The key is chosen from 24 candidates by comparing the song's overall strength per pitch class (chroma) with typical major and minor distributions (Krumhansl-Kessler profiles). Relative keys (such as C major and A minor) share the same notes and are easy to confuse, so the correct key may appear as the second candidate. Songs that modulate often are averaged over the whole song. To change the key, use the Pitch shifter; to remove the vocals and change the key together, use the Karaoke track maker.
Frequently asked questions
Why is the BPM double (or half)?
This often happens with songs that can be counted two ways. The real tempo may be twice or half the value shown. The BPM is not estimated for audio shorter than 8 seconds.
What about songs that change tempo or key?
Both the BPM and the key are estimated from the whole song. A song that changes tempo gets one representative value, and a song that modulates often gets the key averaged over the whole song. To check sections separately, split them with Trim audio first.
What is the Camelot code?
A key notation used by DJs: a number from 1 to 12 plus A (minor) or B (major). Keys with the same number or one apart are said to blend smoothly.
Does it work on phones or with video files?
Yes. No app is needed: open this page in your browser and drop songs or videos such as MP4 and MOV. Results are shown on screen and can be saved as a JSON file. Files are not uploaded.
Help us improve the service
If a conversion fails, sending us the circumstances helps us track down the cause. Knowing which devices and formats fail most often, and how long processing takes, lets us revise the supported formats and fix the bugs behind them. If you don't mind, leaving this on is a real help.
What is sent
The tool you used and the settings you chose (output format, quality, etc.), your device specs (GPU, memory, core count), the input format with a rough size, how many files succeeded or failed and how long it took, and the error type and details when something fails.
What is never sent
The files themselves, file names, text, subtitles or prompts you add to a video, and IP addresses. The data goes only to this site's own server, never to a third-party service.