What does arrow spine rating mean?

Spine rating is the deflection in thousandths of an inch when a 1.94 lb weight is hung from the center of a 28-inch arrow shaft. A 340 spine deflects 0.340 inches — stiffer than a 500 spine which deflects 0.500 inches. Lower number = stiffer.

Why does bow type affect spine selection?

Compounds let off peak weight at full draw (typically 65–80%), so the arrow experiences less of the labeled draw weight. Recurves transfer more energy directly. Traditional bows shoot off the shelf, adding paradox that requires a weaker (more flexible) spine to recover correctly.

What if my result falls between two standard spine ratings?

Always round toward the stiffer spine (lower number) when in doubt. An arrow that is slightly too stiff is easier to tune by adjusting point weight or nocking point height than one that is too weak.

Does point weight affect spine selection?

Yes — heavier points (125–150 gr) effectively weaken the dynamic spine. Add roughly 5 lbs to your draw weight input for every 25 gr above the standard 100 gr field point to compensate.

What is dynamic spine vs static spine?

Static spine is measured on the bench (deflection test). Dynamic spine is how the arrow actually behaves during a shot, which is affected by point weight, arrow length, bow type, and arrow rest style. This calculator estimates dynamic spine from your inputs.

Arrow Spine Calculator

Name: Arrow Spine Calculator
Availability: InStock
Author: Nham Vu

Enter your draw weight, draw length, and arrow length to find the right arrow spine stiffness for your setup.

Your Setup

Bow Type

Peak Draw Weight (lbs)

Draw Length (inches)

Measured from nocking point to throat of grip + 1¾".

Arrow Length (inches)

Nock groove to end of shaft, not including the point.

Point Weight (grains, optional)

Leave blank for standard 100 gr field point.

Standard Spine Ratings

Spine	Deflection	Typical Use

Summary

Enter your draw weight, draw length, and arrow length to find the right arrow spine stiffness for your setup.

How it works

Enter your bow's peak draw weight in pounds.
Enter your draw length in inches (tip of middle finger to the throat of the grip, plus 1¾").
Enter the arrow length you intend to shoot (nock groove to end of shaft, excluding point).
Select your bow type (recurve, compound, or traditional/longbow) for a type-specific adjustment.
The calculator applies the standard spine formula and outputs the recommended dynamic spine rating.
Compare the result against the AMO/ATA spine deflection chart to pick the right shaft.

Use cases

Selecting arrows for a new compound bow setup.
Switching from target to hunting arrows and re-matching spine.
Helping beginner archers choose off-the-shelf shaft options.
Verifying an existing arrow selection before buying in bulk.
Cross-checking a pro-shop recommendation.
Adjusting spine selection after adding a heavier field point.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu