385 grains
Shaft 242 grPoint 100 grInsert 15 grNock 10 grFletching 18 gr
Grains per pound6.4 gr/lb
Arrow weight builder
Arrow weight changes speed, energy and how quiet your bow is. Build yours part by part to see where it lands. Add up shaft, point, insert, nock and vanes to get your finished arrow weight and grains per pound.
How to use it: Pick each part of your arrow from point to vanes, set your shaft length, and the total grains and grains per pound add up on the right.
// The calculator
// The math
How it’s calculated
Shaft weight = GPI × shaft length (grains per inch × inches), rounded to the grain. Total arrow weight = shaft + point + insert + nock + fletching.
Grains per pound = total weight ÷ your draw weight, to a tenth. Under 8 gr/lb is too light for most traditional bows, 8–9 is light, 9–11 is a common traditional build, 11 and up is heavy.
A worked example
An 8.5 GPI shaft at 28.5″ = 242 gr. Add a 100 gr point, 15 gr insert, 10 gr nock and 18 gr of vanes: 385 gr. From a 40 lb bow that’s 385 ÷ 40 = 9.6 gr/lb, a common traditional build.
The full explanation: Grains per pound in the glossary.
// FAQ
Questions about arrow weight
Quick answers about grains, FOC and building a hunting arrow.
How heavy should my arrow be?
For a traditional bow, aim for 9 gr/lb or more. Many recurve and longbow makers warn that lighter arrows can damage the limbs. Check your manual.
Where do I find GPI?
It’s printed on the shaft box and the maker’s spec sheet, next to the spine. It changes with spine, so look up the exact one you shoot.
How do I make my arrow heavier?
A heavier point is the easiest fix, but it also makes the arrow act weaker, so recheck your spine. A heavier shaft or brass insert adds weight too.
// More tools
