In the MOI matching process it is helpfull to know a value of the whole club MOI before the club is assembled. It allows to select the right components for the designed club and proper matching of the club set.
The calculator below gives a good approximation of MOI (moment of inertia) of a golf club basing on parameters of its components. The calculation uses a few simple values: the weight of the head, the desired length of the club, the weight of the grip, the weight and the length of the uncut (raw) shaft.
Some fields contain the default data. These values can be modified if you consider to use heavy ferrule or adapter or bore-through club heads (small BBGM). In most cases the difference between results of calculations doesn’t exceed value of 3 kg*inch² (one point), but not always. The impact of tip trimming is usually negligible and it could be ignored.
The picture below shows how to measure BBGM.
Please remember that the result the calculation is only an approximation because of many factors that determine the exact value of MOI. It depends of influences of weight distribution of weight in the shaft, the center of gravity in the head, the lie angle of the head, weight of epoxy used for assembling the head etc. So it is highly recommended to measure the MOI of the assembled club and apply a necessary adjustment if it is needed. Very useful is measurement of the temporarily (provisionally) assembled club.
update: January 2018