|This is an estimate of how heavy a typical 29" long arrow (with 100 grain tip, 4" vanes, w/inserts and nocks installed) would be if built from a particular arrow shaft. Keep in mind, this is just an estimate intended to assist you in comparing the various arrow shafts. If you order custom arrows, don't expect your finished arrow mass to perfectly match the estimate. This is a ballparking tool.
If you want to really get down to the grain, you must know the exact mass of each arrow component (shaft, nock, insert, fletching, tips, collars, other hardware) plus the exact mass of the glue used in construction. That's pretty tough to do. We have an online arrow build simulator in Chapter 4 of our Carbon Arrow University which takes many of those attributes into account. It will surely provide you with an even more accurate estimate. But don't hold us to the grain here. Even the simulator is still just an estimate.