BPM Tap Tempo & Key Analyzer
Tap spacebar or click the button to measure your track's tempo. Enter the musical key and see which keys mix harmonically using the Camelot Wheel - the DJ standard for blending tracks smoothly. Nothing uploaded.
Or press Space / Enter
Compatible keys
Learn more: BPM measurement and harmonic key mixing
How tapping becomes a BPM number
Each tap stores a timestamp, and the gaps between consecutive taps are where the BPM comes from. The tool averages the most recent gaps and divides that average into 60,000 milliseconds, so an average gap of 500 ms shows as 120.0 BPM.
The "Average over" buttons decide how many gaps feed that average: the last 4, the last 8, or every tap since your last reset. A 4-tap window follows you quickly when you correct your timing, while the full history smooths out one badly placed tap. The engine holds your 32 most recent taps and discards anything older.
A BPM reading appears from the second tap onward, and the consistency figure from the third.
What the consistency percentage measures
Consistency is 100 minus the coefficient of variation of the gaps in the current window, rounded to a whole number and floored at 0. It compares the spread of your gaps against their average, so it scores how evenly you tapped rather than whether you matched the track.
Say four gaps come in at 500, 520, 480 and 500 ms. The average is 500 ms and the standard deviation about 14 ms, which is 2.8 percent of the average, so the display reads 97%. The tool flags anything from 80% up as good, 55% to 79% as borderline, and below 55% as poor.
The row of dots below the display grades every gap on its own. A gap within 5% of the window average counts as good, one within 15% as borderline, and anything further out as poor, which is how you find the single tap you fumbled.
The Camelot Wheel is the circle of fifths, relabelled
Every key gets a clock position from 1 to 12 and a letter: A for the inner ring of minor keys, B for the outer ring of major keys. In this tool's table 8A is Bb minor and 8B is Db major, while 5A is Db minor and 5B is E major.
One step clockwise on the same ring moves the key up a perfect fifth. 8A (Bb minor) to 9A (F minor) is a fifth, and so is 1B (C major) to 2B (G major). The wheel is the circle of fifths with number-and-letter labels on top of it, which reads faster in a dark booth than key signatures do.
Type a key and the tool highlights three others: the relative key at the same position on the opposite ring, plus the two positions either side of yours on the same ring. For 8A that gives 8B, 7A and 9A.
Where classical tempo names land on club tempos
The tempo label under the BPM figure uses the Italian markings, with these boundaries: Andante runs up to 108, Moderato from 108, Allegro from 120, Vivace from 156, Presto from 176, and Prestissimo from 200 upward. Below 76 the label steps down through Adagio, Larghetto, Largo and Grave.
Those bands were set long before club music and still land in sensible places. A 124 BPM house track reads as Allegro, a 174 BPM drum and bass track sits near the top of Vivace, and a 90 BPM hip hop beat comes out as Andante.
FAQ
Are the three compatible keys interchangeable?
They are three different moves. The relative key keeps the same notes and swaps the major or minor feel, while the two neighbours on your own ring shift the pitch centre by a fifth, which is the bigger change to hear.
Why does the key box accept both Am and 5A?
Track metadata arrives in whatever notation the software that wrote it prefers. The parser reads Camelot codes like 5A directly and also checks an alias table covering forms such as Am, A minor, Amin, C major, Cmaj and sharps like C#m, so you can paste whatever your library shows.
Does matching BPM and key guarantee a clean transition?
No. They are two separate filters, and neither says anything about energy, arrangement or how the two basslines sit together. Use them to shortlist tracks, then listen to the blend.