600 spine
Stiffer →Weaker
Chart row35–40 lb
Arrow length28"
lb ↓ · length →27"28"29"30"31"32"
20–25 lb
25–30 lb
30–35 lb
35–40 lb
40–45 lb
45–50 lb
50–55 lb
55–60 lb
60–65 lb
Arrow spine finder
Spine is how stiff an arrow is. Match it to your bow and arrows fly straight. Miss it and no amount of form fixes the flight. Set the draw weight you actually pull and your arrow length. The chart lights up your starting carbon spine.
How to use it: Set your draw weight at your draw length, pick your arrow length (nock throat to end of shaft), then read your starting spine on the right.
// The calculator
// The math
How it’s calculated
No formula: spine comes off a chart. The finder uses Sportsman’s Warehouse’s carbon arrow spine chart (100 gr point, 27–32″ arrows), for a recurve shot with fingers.
Your draw weight picks the 5 lb row (35–39 lb sits in the 35–40 row) and your arrow length picks the column. Use the weight you actually pull at your draw, not the number on the limbs.
A worked example
37 lb at your draw and a 28″ arrow: the 35–40 lb row, 28″ column = 600 spine.
The full explanation: Arrow spine in the glossary.
// FAQ
Questions about arrow spine
Quick answers about spine numbers, shaft materials and cutting arrows.
What do spine numbers mean?
For carbon, the number is how far the shaft bends under a test weight, in thousandths of an inch. A 500 bends less than a 700, so lower numbers are stiffer.
Carbon or aluminum to start?
Carbon for most adults: it’s tougher and more forgiving of small spine mismatches. Aluminum is cheaper, easy to straighten and a good fit for very light bows.
Can I just cut my arrows shorter?
Yes, and it makes them stiffer. That’s why the finder uses your arrow length. Never cut shorter than your draw plus 1″.
// More tools
Draw length calculatorArm span to draw, bow and arrow length.Open tool →Arrow weight builderTotal grains and grains per pound for your arrow.Open tool →Ethical shot checkerIs your setup and shot ready for the animal?Open tool →Arrow energy calculatorKinetic energy and momentum on the game chart.Open tool →
