Enter a starting BPM, ending BPM, and the duration between them to measure exactly how much a tempo drifted, in total and per minute.
Useful for checking whether a live take rushed or dragged, or for quantifying how much a drummer or click-free section shifted tempo over a section of a song.
Tempo Drift Estimator
Starting BPM:
Ending BPM:
Duration (minutes):
How This Estimator Works
The total drift is simply the ending BPM minus the starting BPM. Dividing that by the duration gives an average drift rate per minute, and dividing by the starting BPM gives the percentage change, useful for judging how noticeable the drift would feel to a listener.
How to Use This Calculator
- Starting BPM: the tempo at the beginning of the section.
- Ending BPM: the tempo at the end of the section.
- Duration: how many minutes elapsed between the two readings.
- Click Estimate Drift to see the total change, rate per minute, and percentage.
Example: a tempo going from 120 BPM to 128 BPM over 4 minutes sped up by 8 BPM (+6.7%), about 2 BPM per minute.
Did You Know?
- A tempo drift of 1 to 2% is generally imperceptible to most listeners, while drifts above 5% are usually noticeable, especially against a static reference like a recorded backing track.
- Live drummers often speed up slightly during high-energy sections and slow down during quiet ones, a natural effect called tempo “push and pull” that click tracks are designed to eliminate.
Frequently Asked Questions
Is some tempo drift normal in a live performance?
Yes, small amounts of drift are common and often go unnoticed. This tool is useful for quantifying exactly how much drift happened, not for judging whether it’s acceptable.
Can I use this for a whole song instead of one section?
Yes, enter the tempo at the very start and very end of the song along with its total duration to get an overall average drift figure.