Find the BPM (tempo) and musical key of any song. Drop in an audio file and Solmi detects the beats per minute and the key automatically — no upload, no signup, and your audio never leaves your device. Supports MP3, WAV, M4A, AAC, OGG, and FLAC.
Upload an audio file and Solmi's BPM finder analyzes it directly in your browser — it decodes the audio, isolates the kick/bass band where the beat lives, detects the peaks, and measures the time between them to calculate the tempo. Nothing is uploaded to a server; the detection runs entirely on your device.
Yes. Alongside the BPM, Solmi estimates the song's musical key (for example, A Minor or C Major) by analyzing the audio's pitch content with a chromagram and matching it against standard key profiles — all in your browser. Treat it as a strong estimate; very chromatic or key-changing tracks can be ambiguous.
They're the same thing — all three find the tempo of a song in beats per minute (BPM). A 'BPM counter' sometimes refers to the tap-along kind where you tap a key to the beat; this tool detects the BPM automatically from the audio file instead, so you don't have to tap.
Tempo detection has inherent octave ambiguity — a song at 75 BPM and one at 150 BPM produce a very similar beat pattern. We show the most likely tempo first, plus half-time and double-time candidates, so you can pick the one that matches how the song feels.
MP3, WAV, M4A, AAC, OGG, and FLAC — any format your browser can decode. Larger or longer files take a little longer to analyze.
Yes, completely free with no signup. Once you know your song's BPM, you can turn the track into a beat-synced music video with Solmi's AI music video generator — also free to start.