I don't weigh my arrows, because the information has limited use. It can come in handy if you plan to push the envelope when shooting light arrows that may be too light. I don't. It may also have some use for target shooters who want to print out sight tapes. Once again, I don't. Typically, using manufacturer provided weights, gets you close enough. In my opinion, it's very important to get that weight towards the front of the arrow, but to do that, you don't have to know the actual weight.

I use to weigh my arrow shafts before building them, but found that I couldn't detect a difference in flight from ones that were only a 5-10 grains difference in weight. Someone shooting at great distances would probably benefit a lot more from this. I also found that some broadheads and even some field tips varied far more than the shafts would.

If you do want to weight them, reloading scales work fine. 1 gram = 15.43 grains.