Archery Arrow Weight Calculator
Created by: Ethan Brooks
Last updated:
Add shaft and component weights to estimate a complete arrow in grains and grams, with a measured-weight comparison and component breakdown.
Archery Arrow Weight Calculator
ArcheryShaft + components • grains and grams
What does this calculator measure?
An arrow weight calculator adds the mass of a bare shaft to the components fitted to one arrow. Enter either a uniform shaft's length and grains-per-inch specification or the measured weight of the cut shaft. Add the point, insert or outsert, nock, fletching, wrap and other material. The result gives the complete arrow weight in grains and grams, with a separate contribution for every component group.
This is a bill of materials for one arrow, not for a pack of arrows. A package may list the weight of one vane, a set of vanes, an insert with a collar, or an already assembled item. Read those descriptions before entering values. The form multiplies only the individual vane or feather weight by its count. All other component fields represent the combined amount installed on one arrow.
Choose the shaft method to match what you actually know. A GPI specification describes linear mass rather than finished-arrow weight. Multiplying it by cut length assumes that it applies uniformly to that piece of shaft. Easton's FAQ notes that tapered and barreled shafts have variable GPI along their length. For those shafts, use a measured bare-shaft weight instead of treating an average catalog figure as an exact cut-length model.
The optional scale comparison helps reconcile your parts list with a completed arrow. A positive difference means the scale reading is heavier than your calculation; a negative difference means it is lighter. Neither result identifies the cause by itself. The calculator records mass only. Shaft spine, balance, component fit and equipment requirements need their own measurements or references, and the initial example values are not recommended specifications.
How the calculation works
For the GPI method, first convert shaft cut length to inches. Multiply that length by the entered grains per inch to get bare-shaft grains. For the measured method, use the entered bare-shaft mass directly and ignore the hidden length and GPI values. In both modes, multiply individual fletching weight by the whole-number count, then add each remaining component once. Keep intermediate values unrounded so that unit changes do not alter the underlying mass.
The gram conversion uses 0.06479891 grams per grain. Component share is its mass divided by total mass, multiplied by 100; shares describe weight contributions, not the locations of the components. The bar chart and table show the same breakdown. If a complete-arrow scale reading is supplied, subtract the calculated total from that reading using matching units. Display rounding can make independently rounded table rows differ slightly from the displayed total.
Formula and symbols
S = L × GPI or measured shaft grains; W = S + point + insert + nock + count × vane mass + wrap + other; grams = W × 0.06479891.
- L: Bare shaft cut length (inches)
- GPI: Uniform shaft mass per inch (grains/inch)
- S, W: Shaft and complete arrow mass (grains)
How to use the calculator
- Choose units and shaft method. Use length × GPI for a uniform shaft, or enter the measured bare-shaft mass. Starting values are an example.
- Account for components. Enter each installed component once. Supply a whole vane count and the mass of one vane. Enter zero for absent items.
- Compare a scale reading. Optionally enter the measured complete-arrow weight; leave it blank to omit the comparison.
- Review the breakdown. Calculate, review component contributions and check any difference against the actual assembled arrow.
Worked examples
A 363-grain component total
A uniform shaft measures 28 inches and is specified at 8 GPI, so its calculated mass is 224 grains. Add a 100-grain point, a 20-grain insert and a 10-grain nock. Three vanes at 3 grains each contribute another 9 grains. With wrap and other material entered as zero, the total is 363 grains, or approximately 23.522 grams. The shaft contributes about 61.7% of the total. This example excludes adhesive; enter its measured contribution if it is part of your accounting.
Using an already weighed shaft
Suppose a cut bare shaft weighs 230 grains. Select the measured method and enter that mass, then use a 100-grain point, 20-grain insert, 10-grain nock and three 3-grain vanes. Add 5 grains for the wrap and 2 grains for adhesive or other items. The complete total becomes 376 grains, about 24.364 grams. If the finished arrow reads 378 grains on your scale, the comparison shows +2 grains. Check the recorded component masses and scale procedure before attributing that difference to a particular part.
Keeping measurements consistent
The first example's 28-inch shaft is 711.2 millimeters. Switching to metric converts the entered length and component masses, while the supplier's GPI number remains 8. Recalculating gives the same 363-grain total. The unit switch changes the display and entry units, not the physical arrow or the meaning of its shaft specification.
Practical applications
- Prepare a parts list for one arrow before assembly. The separate shaft, point, insert, nock and fletching rows make omissions easier to spot than a single handwritten total. Record which accessories are already included in each advertised component weight.
- Compare an existing setup with a proposed component substitution. Save the first result, change the relevant mass and recalculate. The change in total quantifies the material difference; it does not predict how the replacement will affect flight or compatibility.
- Reconcile supplier specifications with a measured assembled arrow. Enter the scale reading to obtain a signed difference. Review the component inventory, measurement resolution and omitted items before deciding whether a discrepancy reflects a real difference between arrows.
- Maintain a consistent record across metric and grain-based tools. A scale that reads grams and a catalog that lists grains can be used in the same workflow. Choose the appropriate input units and retain the named specification with your saved result.
- Account for a bare shaft that does not suit the uniform GPI model. The measured method avoids assuming that shortening a tapered or barreled shaft removes the same mass per inch everywhere. It also works when a reliable direct weighing is available.
- Document what an example excludes. A zero for wraps or other material means those items contribute nothing to this calculation; it does not imply that all actual adhesive or accessory masses are negligible. This keeps comparisons between saved configurations understandable.
Tips for consistent measurements
Check the exact shaft model and spine when copying GPI, and measure the bare cut shaft rather than borrowing the FOC arrow-length measurement. Use a consistent weighing procedure and confirm the scale's unit indicator. Enter 0 for an absent component; leave only the optional complete-arrow comparison blank. When a part combines an insert, collar or weight, account for the combined assembly once instead of repeating its included pieces in another field.
Keep a short equipment note with exported results so you can identify the build later. Measure the complete arrow after assembly and revisit your component list if the comparison differs. For balance information, use the FOC calculator with actual distances; a mass breakdown cannot locate the center of balance without positional information. Treat the precision shown by the calculator as arithmetic precision, not proof that catalog or scale inputs are equally precise.
Frequently asked questions
Does GPI include the point and nock?
For the bare-shaft convention used here, it does not. GPI multiplied by shaft cut length gives shaft mass, while the point, nock, insert and fletching are added separately. Check whether your supplier's listing instead describes a partially assembled product. Enter each installed item once, and do not add components already included in a measured assembly weight.
Can I enter grams instead of grains?
Yes. Select millimeters and grams to convert current lengths and component masses. The GPI field intentionally remains in grains per inch because that is the supplier specification being entered. The result always includes both total grains and grams. Unit switching preserves a blank optional reading and does not create a scale measurement for you.
What should I enter for three vanes?
Enter 3 as the vane or feather count and the weight of one vane in the individual-weight field. For example, three 3-grain vanes contribute 9 grains. Do not enter their combined 9-grain weight as the per-vane value, because that would count 27 grains. The result table states the count used in the calculation.
Why is the measured arrow heavier than the estimate?
A positive measured-minus-calculated difference can indicate an omitted item, a component that differs from its stated mass, or a measurement discrepancy. Check glue, wraps, bushings and collars, and confirm that the scale and entered units match. The calculator reports the difference without assigning a cause; repeat measurements and review the actual parts before drawing a conclusion.
Can this calculate tapered or barreled shafts?
Use the measured bare-shaft method for those cases. A single GPI figure can be misleading when linear density changes along the shaft, especially after cutting. Weigh the actual bare shaft, enter that mass and add the installed components separately. Length and GPI fields are ignored in this mode, even if they contain values from an earlier calculation.
Does total arrow weight tell me FOC or spine?
No. Total mass does not identify where that mass lies along the arrow, and it does not determine the shaft's stiffness. FOC requires a measured balance point and reference length. Spine selection requires the relevant manufacturer's chart and setup information. Use the mass result as one recorded measurement rather than treating it as a complete equipment assessment.
Sources and measurement scope
- Easton Archery: Archery FAQs — how arrow weight is measured — Undated online FAQ; How does Easton measure arrow weight?. Accessed 2026-10-01. GPI is bare-shaft mass per inch, excluding components; tapered and barreled shafts have varying linear density.
- NIST: Guide to the SI, Appendix B.9 — conversion factors — SP 811 online Appendix B.9; Length; Mass and Moment of Inertia. Accessed 2026-10-01. Inch-to-meter and grain-to-kilogram conversion factors; no archery selection guidance.
Worked examples use illustrative measurements. These tools do not select equipment or prescribe a preferred setup. Any optional manufacturer comparison uses the reference entered by the user.