Equine BPM timings are very often misquoted and this very basic measurement has been somewhat confused by the many 'unaware' people who incorrectly quote the speed of music that matches equine BPM as the speed at which the horse moves.
Equine BPM (above 14:2hh) lie between these parametres:
Walk: 50 - 65 BPM
Trot: 75 - 90 BPM
Canter: 95 - 110 BPM
Passage/Piaffe 60 - 65 BPM
Music that matches a walk of 50 BPM might well go at speeds of 100, 200 (or even 25, 12.5) BPM etc. but anyone with an inkling of common sense quickly realises that some horses can't be walking at 25 BPM with others zooming along at over 200 BPM! The concept is, of course, hideous.
However, confusion still abounds because people take BPM advice from musicians who know nothing about horses, and from eminent equestrians who know little about music.
By far the easiest way to measure equine BPM is to put a coloured bandage on one of the hind legs and have someone count how many times that leg touches the ground in one minute. Yes ... it's that simple!
You can, of course, do it yourself and feel it through your seat while riding. Counting for 15 seconds and multiply the result by four makes it easier still, but as this makes all the people taking BPM with calculators and metronomes feel rather gullible you should only consider doing this if you want to show-off or have neither time nor money to waste.
Remember to work-in your horse before taking BPM and you will need to ascertain a BPM for each gait.
Equine physiology and the laws of physics dictate that canter is roughly twice the speed of walk, with trot midway between the two.
Your horse's level of training (balance), conformation, and even shoeing have a bearing on the figures and the trot and canter BPM will therefore change as your horse develops its musculature.
If you are training below PSG or have unequal lateral flexion, it is worth taking a BPM reading for each rein in canter to check that there is not a huge difference in speeds. If there is, take an average ... though ideally you will work on the flexion till both BPM are the same!