Tap tempo — find the BPM

BPM stands for beats per minute: how many beats fit into one minute. At 60 BPM there is one beat every second, at 120 BPM two, and the gap between beats in milliseconds is 60,000 divided by the BPM. The beat is the pulse you tap your foot or nod your head to; in most pop, rock and dance music it is the quarter note.

The small number with one decimal next to the whole BPM is there because real tempos are rarely whole numbers when a band plays without a click. Electronic music is usually made at an exact tempo, so a tapped reading of 127.8 there most likely means 128.

The tapper also names the tempo with the Italian marking a musician would use, from Largo to Presto, which helps when you are comparing a recording with the tempo word printed on sheet music.

Tap along with the part of the song where the beat is clearest, usually the chorus, where the kick drum and snare are loud. Tap with a finger rather than the whole arm and keep going for 8 to 16 beats: the reading after four taps is already close, and more taps average out the small timing errors every human tap has.

Without any tool, count the beats for 15 seconds on a clock and multiply by 4, or count for 30 seconds and multiply by 2. It works, but every beat you miscount in 15 seconds changes the result by 4 BPM, so tapping is more precise.

Songs played live without a click drift: they push ahead in a chorus and settle back in a verse. Tap different sections and you may get readings a few BPM apart; that is the song, not the tapper. An average over a whole section is the tempo to practice with.

The most common surprise is a reading that is half or double what you expected. A song can be felt in the slow pulse of the snare or the fast pulse of the hi-hat, and both are real. Listings usually follow the habit of the genre: drum and bass is given at around 170 BPM even though its bass line often feels half that, and dubstep is given at 140 while heads nod along at 70.

To check, listen for the snare. In most pop and rock songs it lands on every second tap when you tap the usual beat. If it lands on every fourth tap, you are tapping double time; if it lands on every tap, you are tapping half time.

The ranges below are rough guides for spotting a half or double reading, not rules; plenty of songs in every style sit outside them.

Producers and guitarists set delay, reverb pre-delay and other time-based effects to note values so the echoes land on the beat. One quarter note lasts 60,000 ÷ BPM milliseconds; halve it for an eighth note and again for a sixteenth, multiply by 1.5 for a dotted note and by 2/3 for a triplet. At 120 BPM that makes a quarter note 500 ms, an eighth 250 ms and a dotted eighth 375 ms; the table under the pad does the math for the tempo you tapped.

A dotted-eighth delay is a classic guitar sound: each echo falls between the notes you play and turns a plain eighth-note line into a rolling sixteenth-note pattern. A quarter-note or eighth-note delay mixed low thickens a vocal without blurring the words.

Some synth and effect settings are in hertz instead of milliseconds. For those, divide the BPM by 60 to get quarter notes per second: 120 BPM is 2 Hz, and an eighth-note rate at the same tempo is 4 Hz.