Find a song's key and BPM from audio

Read the full song before the individual parts

The full mix gives the analyzer more harmonic and rhythmic context than a sparse vocal or bass line. Begin with its estimated key and BPM, then compare the selected stem results. A different stem estimate is not proof that the musicians are playing in different keys or at different speeds.

Sattari AutoKey scans the full audio for an overall key; it does not map key changes. Tempo analysis samples up to three 20-second windows, so tempo changes can fall outside those windows. The report cannot map every section or replace careful listening.

Key is a suggestion, not a verdict

A key estimate summarizes the tonal pattern the analyzer hears. Relative major and minor keys share the same pitch collection, so a result can favor one even when the other feels like home. Repeated notes, unusual tunings and separation artifacts can also affect the estimate.

Prominent notes are pitch classes, not a melody, a bass transcription or a list of chords in time. Try the suggested home note on your instrument and compare it with the ends of phrases. If the result disagrees with the recording, trust a listening check over a confident-looking label.

Drum stems are not assigned a musical key. Weak or unsuitable tonal material can be shown as undetermined instead of receiving a useful key estimate.

BPM versus detected pulse

BPM means beats per minute. The analyzer looks for a repeating pulse, which may correspond to the beat, half the beat rate or twice it. For example, a pattern that feels like 80 BPM may generate an estimate around 160 BPM.

Count steady beats along with the original, then check which interpretation matches the phrasing. A vocal line with long gaps is a weak tempo reference; the drum stem often supplies clearer rhythmic information. Estimates do not create a beat grid or guarantee that a song stays at one tempo.

Keep an analysis report with your stems

1. Run separation and inspect the original-song summary and each selected stem. Read the evidence labels as well as the key and tempo numbers.
2. Open the analysis details to review duration, working sample rate, channels, sample peak and RMS levels. Those audio levels are measured across the audio, unlike the sampled musical analysis.
3. Download the JSON analysis report for a machine-readable record. The stem ZIP includes the report too. Save your outputs before closing or leaving the separator.
4. Use the findings to pick a practice starting point in Learn or organize a Studio session. Verify the musical choices by ear before building an arrangement around them.