BPM & Key Finder

BPM & Key Finder listens to a song and tells you its tempo in beats per minute and its musical key. Drop in one track or a whole batch of MP3, WAV, M4A, FLAC, OGG or AIFF files, or a video, and each one gets a row with its BPM, key, Camelot code and how sure the measurement is.

It is built for DJs planning a set, producers picking samples that sit together, dancers and fitness instructors choosing music by pace, and singers checking whether a song suits their range. The tempo comes from where new sounds start, matched against every tempo from 40 to 240 BPM and then fine-tuned to a hundredth of a beat. The key comes from the notes heard most often, compared with two well-tested key profiles, with the recording’s tuning corrected first.

Software can be fooled, so the tool helps you check. Play any file with a click on every detected beat and hear straight away whether it stays in time, switch to half or double speed with one tap, or tap along yourself. Every file is read and analysed in your browser, so unreleased tracks never leave your computer.

1. Press “Choose songs” or drop audio or video files on the box. You can add several at once.
2. Wait a few seconds while each file is opened and measured. The first file’s tempo, key and notes chart appear at the top.
3. Press “Play with click” to hear the song with a click on every beat. If the click drifts, try Half or Double, or change the Tempo range.
4. Choose any file name in the “All files” table to see it in detail.
5. Press “Download CSV” for a spreadsheet of every result, or “Copy table” to paste it somewhere.

• Tempo from 40 to 240 BPM, measured to a hundredth, with half and double alternatives and a choice of tempo range.
• Key with relative major or minor, the runner-up key, Camelot wheel code and keys that mix well with it.
• Confidence for both tempo and key, plus how much of the song agrees with the tempo found.
• Tuning check: shows when a recording sits more than a few cents sharp or flat of A = 440 Hz.
• A chart of the twelve notes heard most, with the key note highlighted.
• Click track player locked to the detected beat, with seek, click on or off and click volume.
• Tap tempo pad that works with a finger, the mouse, or the T key.
• Batch of up to 50 files, CSV download and copy as a table for spreadsheets.

• Many songs can honestly be counted two ways: drum and bass is 174 or 87, a slow ballad 70 or 140. Pick the one that matches how people dance or clap to it.
• Choose the tempo range that fits your music before adding files; it decides between half and double speed when both fit.
• Songs that change key or tempo part-way get the most common one. A low confidence score is the hint to listen with the click.
• Camelot codes make mixing simple: move one number up or down, or swap A and B with the same number.
• Very long files such as DJ mixes are measured on their first 15 minutes.