Swing Groove Timing Calculator

Swing timing is a controlled violation of even subdivision. A beat lasting 60000/BPM milliseconds is normally split into two equal eighth notes, but a swung pair allocates a fraction s of the beat to the downbeat note and (1 - s) to the offbeat note. Researchers call the resulting quotient the beat-upbeat ratio, or BUR. At s = 0.50 the BUR is 1.00 and the feel is straight; at s = 0.667 the BUR is 2.00, which is exactly the first-plus-second of a triplet and is what notation software means by a shuffle. This calculator reports both the two note lengths in milliseconds and the BUR, plus straight delay times for quarter, eighth, dotted-eighth, sixteenth and triplet values at the same tempo. Practical values cluster tightly. Light swing sits near 55 to 58 percent, medium swing near 60 to 64 percent, standard triplet swing at 66 to 67 percent, and heavy blues or boogie shuffle at 70 to 75 percent. Above roughly 78 percent the offbeat note becomes a grace note and the groove reads as dotted rather than swung. The main caveat is that a single swing number is a simplification: measured BURs in recorded jazz fall as tempo rises, typically from around 2.5 at 100 BPM toward near 1.0 above 300 BPM, and soloists routinely swing less than the drummer behind them. Swing amount also usually applies only to the primary subdivision, so applying an eighth-note swing setting to sixteenths in a DAW will change the feel far more than intended.

Uneven subdivision predates jazz. Baroque performers applied notes inegales, holding the first of a pair of stepwise notes longer, and the practice was described in French treatises through the seventeenth and eighteenth centuries. What became known as swing crystallised in African American dance bands of the 1920s and 1930s, and the word entered common usage as a genre label after Duke Ellington recorded It Dont Mean a Thing (If It Aint Got That Swing) in 1932. Because the effect resists ordinary notation, publishers settled on printing a shorthand at the top of the score equating a pair of eighth notes to a quarter-plus-eighth triplet, which is where the 2:1 default comes from. Swing became a numeric parameter rather than a feel when drum machines and sequencers adopted quantisation. Roger Linn built swing into the LinnDrum lineage and then into the Akai MPC60, released in 1988, exposing it as a percentage from 50 up through the high 60s and 70s so producers could dial in groove against a rigid grid; that percentage convention is why nearly every DAW today labels the control the same way. From the 1990s onward music-information-retrieval researchers began measuring swing empirically from recordings rather than assuming a fixed ratio, and studies of large jazz corpora established the now standard finding that the beat-upbeat ratio shrinks steadily as tempo increases.