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Beatgrid drift
Beatgrid drift is a grid that lines up at the start of a track and slides out of alignment later — the tempo the software stored is close to the real one but not equal to it.
Measured in our catalog
Where our two tempo readings of a file disagree by more than 2 BPM, 54.8% are out by a musical ratio — double, 4:3 or 3:2.
Every analysed track carries the tempo we publish and the raw analyser reading. They differ by more than 2 BPM on 59,888 of 443,083 tracks, and only 6,295 of those differ by less than 10%. The median ratio across all of them is 1.5× — so the common failure is a whole different pulse, not a fractionally wrong one. A grid that drifts slowly is the rarer case, and it is the one nudging fixes.
17,642
Disagree by exactly 2×
10,948
By 4:3
4,220
By 3:2
6,295
By less than 10%
| Disagreement | Tracks | What it is |
|---|---|---|
| Exactly 2× | 17,642 | Half-time — the pulse you feel, not the one written |
| 4:3 | 10,948 | A triplet or shuffled feel counted straight |
| 3:2 | 4,220 | A dotted pulse taken as the beat |
| Under 10% | 6,295 | Genuine drift — the kind you nudge out |
Measured on 11 August 2026 across public tracks carrying both a published BPM and a raw analyser BPM, counting only pairs more than 2 BPM apart (59,888 of 443,083), with ratios matched to ±2%. Method: how we correct half-time BPM detection.
Why it matters
Drift is the failure mode that hides. A grid that is wrong at bar one gets fixed immediately because the mix falls apart in front of you; a grid that is 0.2 BPM out sounds perfect through the intro and is a beat late by the outro, which is when you are mixing out of it.
The other cause is more interesting, and the numbers below are about it: a detector that gets a tempo wrong usually does not get it slightly wrong. It counts a different pulse in the same music, and is then exactly right about that instead.
Frequently asked
Why does my beatgrid drift halfway through a track?+
Because the stored tempo is fractionally wrong, so the error accumulates: a fraction of a BPM is inaudible for a phrase and a beat out by the end. Anything not recorded to a click drifts for real, and no single tempo will hold it.
How do you fix a drifting beatgrid?+
Re-anchor the grid on a downbeat late in the track rather than at the start, then correct the tempo until both ends line up. If the record was played by hand, it needs multiple grid markers rather than a better number.
Why is the detected tempo exactly half of the real one?+
Because the analyser locked onto the pulse you feel rather than the one the music is written to — the single most common disagreement in our catalog, on 17,642 tracks.
Related terms
Beatgrid
A beatgrid is the map your DJ software lays over a track marking where every beat falls. Once it is right, sync, looping and quantise all work; once it is wrong, everything built on top of it is wrong too.
Sync
Sync matches one deck’s tempo to the other automatically and holds it there, using the beatgrid the software calculated. It removes the arithmetic of beatmatching, not the decision about which record follows which.
Half-time
Half-time is a groove that feels half as fast as it counts — the snare lands every other bar instead of every other beat. Drum & bass written at 174 BPM is felt, and often detected, at 87.
BPM
BPM — beats per minute — counts how many beats land in sixty seconds. It is the first number a DJ checks, because two tracks have to agree on tempo before anything else about them matters.
Explore: Why tempo detection halves · Tap a tempo yourself · Beatgrid · All DJ terms