BPM, key & mood finder
Drop an audio file and get its tempo, key, mood, style and its energy, brightness and density levels in seconds. Free, no sign-up, and your file is deleted as soon as the analysis finishes.
- BPM (tempo) detection
- Key and mode detection
- Mood detection
- Musical style detection
- Energy, brightness and density measurement
- Confidence score on every result
Drop your audio file here
MP3, WAV, M4A, AAC, OGG or FLAC — 20 MB max
What the BPM of a beat is for
BPM (beats per minute) is the tempo of the track. It is the first thing a rapper or a buyer looks at, because it decides whether the beat fits their flow. On marketplaces like BeatStars it is also a search filter: a beat with no BPM filled in simply does not appear in filtered results.
Common ranges: modern trap often sits between 130 and 150 BPM (felt at half time, so around 65-75), UK drill between 138 and 145, boom bap between 85 and 95, afrobeat between 100 and 110. These are not rules but expectations — departing from them should be a choice, not an accident.
Why the key matters just as much
The key tells you the note and mode (major or minor) the track is built on. It serves two very concrete purposes: letting an artist know whether the beat sits in their range, and letting an engineer pick vocal harmonies that do not clash.
The mode also sets the emotional colour. Minor dominates trap and drill because it carries tension. A beat in major does not sell worse, but it speaks to a different register — better to own that than to stumble into it.
Mood and style: the tags that actually sell
On BeatStars and on YouTube, BPM and key only help buyers who already know what they want. Mood and style are what people stumble onto: "dark trap type beat", "melancholic piano beat", "aggressive drill instrumental". A beat without those tags shows up in filtered searches only, never in the searches driven by a feeling.
The tool returns mood and style in the exact vocabulary of the BeatStars form — not as an "energy" or "danceability" score you have to translate yourself. You also get three cursors: energy (level, hit, tempo drive), brightness (the low/high balance of the spectrum) and density (onsets per second). Those are the real measurement; the label is just one reading of them.
Why show the cursors rather than a single word: a beat sitting between two moods flips from one label to the other on very little, while the cursors barely move. A low mood confidence means exactly that is happening — trust the cursors and decide by ear.
How the detection works
Tempo is estimated from the onset envelope of the track, whose autocorrelation reveals the dominant periodicity, then corrected for harmonic errors — that is what keeps a 140 BPM beat from being reported as 70 or 280. The key is determined by correlating the pitch class profile against the Krumhansl-Schmuckler profiles.
The mood combines spectral measurements — loudness in decibels, centroid, rolloff, flatness, percussive-to-harmonic ratio, onset density — normalised and then crossed with the mode and the tempo. The mode (major or minor) carries weight but never decides alone: that is the difference between a measured mood and a key shown twice under two names.
No automatic detection is infallible. Heavily syncopated tracks, tracks without clear drums, and tracks with shifting tempo remain hard. The confidence score tells you how clean the result is: below 70%, check by ear before publishing the value.
What happens to your file
Nothing. The file is received, analysed on its first 60 seconds, then deleted from the server — whether the analysis succeeded or failed. It is not stored, not listened to, not used for anything else. No account is needed and no personal data is requested.
FAQ
Is the BPM finder really free?
Yes, and no sign-up is needed. The only limit is 5 analyses per hour per IP address, to keep the tool from being repurposed as a bulk analysis service.
Is my audio file kept?
No. It is deleted from the server as soon as the analysis ends, successful or not. No storage, no reuse.
Which formats are accepted?
MP3, WAV, M4A, AAC, OGG and FLAC, up to 20 MB. Only the first 60 seconds are analysed, which is enough for both tempo and key.
How reliable is the detection?
On a beat with clean drums, very reliable — and every result comes with a confidence score. Heavily syncopated or variable-tempo tracks remain hard to analyse automatically: below 70% confidence, verify by ear.
Why is the tempo double or half what I hear?
That is the classic half-time ambiguity: a trap beat felt at 70 is usually written at 140. The detection corrects these harmonic errors, but the convention it reports is the written tempo — the one you put in a beat title.
What do the energy, brightness and density levels mean?
Energy combines loudness, percussive hit and tempo: it is the perceived intensity. Brightness measures the low/high balance of the spectrum — a dark, muffled beat sits low, a crisp one sits high. Density counts onsets per second: two beats at the same tempo, one in hi-hat eighths and one in quarters, separate clearly here. All three run from 0 to 100 and are the real measurement; the mood label is just one reading of them.
How do I find the mood and style of a song?
Drop the file here: the tool returns the mood (dark, aggressive, melancholic, chill…) and the style (trap, drill, hip-hop, R&B…) alongside the BPM and key, with no account to create. The values come from the vocabulary beat marketplaces use, so they transfer straight into an upload form.
How reliable is the detected mood?
Less reliable than the tempo, and the tool says so: every mood comes with its own confidence score. Clear-cut cases — a dense aggressive drill, a calm piano loop — come out right. Beats sitting between two moods can flip from one label to the other, which is why the three cursors are shown next to it: those do not flip. Treat the label as a starting point to adjust, not a verdict.
Why BeatStars tags rather than an energy score?
Because an "energy" or "danceability" score does not map onto anything. The BeatStars upload form expects a genre and moods from a closed list: the tool returns values from that list directly, rather than a number you have to translate yourself.