Arrow Diameter Chart: Shaft OD by Model and Class
Carbon arrow shafts fall into a few standard diameter classes: ultra micro at about 0.166 inches, micro or 4mm at 0.204 inches, 5mm at 0.244 to 0.246 inches, and 6.5mm at roughly 0.250 to 0.257 inches. Diameter is fixed within a shaft family and does not change with spine, because manufacturers vary wall thickness instead.
Arrow diameter is the spec most often misunderstood, because archers expect it to move with spine. It does not. Within any shaft family the outside diameter is constant and the wall thickness changes to produce each spine. Diameter is therefore a property of the model you choose, and this chart maps the common families to their nominal diameters.
Shaft outside diameter by model family
Diameters below are nominal figures as marketed. Individual models vary by a few thousandths of an inch, and manufacturers do not all measure at the same point on the shaft, so treat these as class identifiers rather than caliper readings. Spine ranges reflect what is commonly offered.
| Shaft family | Maker | Nominal OD | Class | Common spines | Typical GPI at 340 |
|---|---|---|---|---|---|
| VAP TKO | Victory | 0.166 in | Ultra micro | 250-600 | 8.5-9.6 |
| Target micro shafts | Easton and others | 0.166-0.185 in | Ultra micro | varies | varies |
| 4mm Axis Long Range | Easton | 0.204 in | Micro, 4mm | 250-500 | 9.5-10.5 |
| Airstrike | Gold Tip | 0.204 in | Micro, 4mm | 250-500 | 9.0-10.0 |
| Pierce | Gold Tip | 0.204 in | Micro, 4mm | 250-500 | 9.3-10.5 |
| RIP TKO | Victory | 0.204 in | Micro, 4mm | 250-500 | 9.0-10.2 |
| X Impact | Black Eagle | 0.204 in | Micro, 4mm | 250-500 | 9.0-10.2 |
| Axis 5mm | Easton | 0.244 in | 5mm | 250-500 | 9.0-9.7 |
| FMJ 5mm | Easton | 0.250 in | 5mm, alloy jacket | 250-500 | 11.0-12.5 |
| Hunter XT and Hunter Pro | Gold Tip | 0.246 in | Standard | 300-500 | 8.2-9.3 |
| Rampage | Black Eagle | 0.245 in | Standard | 300-500 | 8.3-9.5 |
| Maxima family | Carbon Express | 0.203-0.295 in | Micro to standard | 250-500 | 8.1-10.5 |
| 6.5mm hunting and target | Easton | 0.257 in | 6.5mm | 300-600 | 8.0-9.2 |
| House-brand entry carbon | Various | 0.244-0.246 in | Standard | 340-500 | 8.5-9.8 |
| Aluminium 20 to 21 series | Easton and others | 0.312-0.328 in | Aluminium | by size code | 9.0-12.0 |
| Aluminium 22 to 23 series | Easton and others | 0.344-0.359 in | Aluminium, indoor | by size code | 11.0-15.0 |
| Indoor fat carbon (27 series) | Various | up to 0.422 in | Indoor line cutter | 350-600 | 9.0-12.0 |
| Traditional wood shafts | Various | 5/16 to 23/64 in | Wood | by lb spine rating | 9.0-14.0 |
Aluminium shafts are sized by a four-digit code where the first two digits are the outside diameter in 64ths of an inch and the last two are the wall thickness in thousandths. A 2216 is 22/64 inches across with a 0.016 inch wall. Wood shafts are graded in pounds of spine rather than deflection, so they do not map onto a carbon spine chart.
What the diameter classes are for
| Class | Nominal OD | Wind drift | Penetration friction | Components | Best suited to |
|---|---|---|---|---|---|
| Ultra micro | 0.165-0.170 in | Lowest | Lowest | Outsert or half-out, collar | Long range, larger game, windy country |
| Micro, 4mm | 0.204 in | Low | Low | Half-out plus impact collar | All-round hunting, the current mainstream upgrade |
| 5mm | 0.244-0.250 in | Moderate | Moderate | Standard insert or HIT style | The default hunting shaft for most archers |
| 6.5mm | 0.250-0.257 in | Moderate | Moderate | Standard insert | Value hunting shafts and some target lines |
| Aluminium | 0.281-0.359 in | Higher | Higher | Swaged or glue-in points | Indoor, traditional, youth, and very consistent budget shafts |
| Indoor fat | up to 0.422 in | Very high | High | Large diameter inserts | Indoor line cutting only, never hunting |
Why diameter matters for wind drift
A crosswind pushes on the side profile of the arrow, and side profile is diameter multiplied by length. Reducing diameter from 0.246 to 0.204 inches removes about 17 percent of the shaft's exposed side area, and going to 0.166 inches removes about a third of it. Less area means less force, which means less lateral acceleration over the same flight time.
Two qualifications keep this honest. First, drift grows roughly with the square of flight time, so the benefit is barely detectable at 20 yards and increasingly obvious past 60. Most bowhunting happens at distances where the difference is small. Second, fletching contributes at least as much exposed area as the shaft does, so a micro shaft with tall vanes can drift more than a standard shaft with low-profile ones. If wind is your problem, look at fletching before you look at shaft diameter.
Where diameter genuinely earns its money is long-range target and open-country western hunting, which is exactly the market micro shafts are sold into. For a treestand hunter shooting inside 30 yards, the case is much weaker, and the money is usually better spent on a rangefinder that removes distance estimation error entirely.
Why diameter matters for penetration
Once a broadhead has cut its hole, the shaft has to follow through it. A narrower shaft contacts less tissue along its length, so it loses less energy to friction. The effect is real, and it is part of why micro shafts are popular in heavy-game builds.
It is also secondary. The dominant factors in penetration are momentum, front of centre and broadhead design, in roughly that order. A 0.166 inch shaft with a wide mechanical head and 8 percent FOC will not out-penetrate a 0.246 inch shaft with a heavy single bevel and 17 percent FOC. Diameter is worth having on your side once the larger levers are set. Work those out with the kinetic energy and momentum calculator and the FOC reference chart.
There is one more diameter effect worth knowing. Micro shafts carry more weight at the same spine because they need thicker walls, and they usually use heavier outserts and collars. Both push the finished arrow heavier and further forward, which improves penetration independently of the diameter itself. Some of the credit micro shafts receive belongs to that extra mass.
Practical consequences for setup
Components. Micro and ultra micro shafts use outserts, half-outs and impact collars rather than conventional inside inserts, because there is not enough bore to glue into. Those parts are heavier and more expensive, and they are not interchangeable between families. Buy components and shafts together.
Rests and quivers. Most modern drop-away rests handle any diameter, but older containment rests and some quiver grippers are sized for standard shafts and hold micro arrows loosely. Check before committing to a dozen.
Squaring and straightness. Smaller diameter shafts are less forgiving of an unsquare end, because the same angular error translates to a bigger relative misalignment of the broadhead. Square the shaft ends with a squaring tool, and spin-test the finished arrow with the head on. Any visible wobble at the tip is a problem to fix before shooting.
Cost. Standard diameter carbon is the value class by a wide margin, and it is what most archers should shoot for their first several dozen arrows. The diameter upgrade is worth revisiting once your tune is solid and you are consistently shooting at distances where it changes anything.
Related tools and charts
- Arrow weight chart: GPI by spine and diameter class
- Arrow spine chart: choose the spine before the diameter
- Total arrow weight calculator: outserts and collars change the sum
- Arrow FOC calculator: micro components shift the balance point forward
- Arrow spine calculator: the input that actually decides the shaft
Frequently asked questions
Does arrow spine change the shaft diameter?
Not within a shaft family. A manufacturer holds the outside diameter constant across a model line and changes wall thickness to hit each spine, so a 340 and a 500 in the same family measure the same on the outside. Diameter changes when you change families, from a 0.246 inch standard shaft to a 0.204 inch micro for example. That is why diameter charts list models rather than spines.
Do micro diameter arrows really drift less in the wind?
Yes, and the reason is straightforward. Crosswind force acts on the exposed side area of the shaft, and a 0.204 inch shaft presents about 17 percent less side area than a 0.246 inch one. The effect is small inside 40 yards and grows with distance and wind speed. Fletching size and time of flight matter at least as much, so treat diameter as one contributor rather than the whole answer.
Do skinny arrows penetrate better?
They reduce friction along the shaft once the broadhead has opened the hole, which helps on deep penetration. The effect is real but modest compared with arrow weight, front of centre and broadhead design. A micro shaft also tends to be slightly heavier at the same spine, which helps penetration in its own right. Think of diameter as a supporting factor, not the primary lever.
Why are indoor target arrows so fat?
Because indoor scoring rewards line cutting. A wider shaft touching the line scores the higher value, so competitors shoot the widest legal shaft at short distance where wind and drop do not matter. Governing bodies cap the diameter for exactly this reason, commonly 9.3 mm under World Archery rules and 0.422 inches under NFAA rules. Verify the current limit with your governing body before a competition.
What components do micro diameter shafts need?
Micro shafts generally use an outsert or half-out rather than a conventional inside insert, because the interior bore is too narrow to accept one with adequate strength. Many are also sold with an impact collar that protects the shaft mouth. Those components are heavier than a standard aluminium insert, which raises front of centre and is one reason micro builds tend to be heavier overall.
Is a bigger diameter arrow easier to shoot?
It can be easier to work with. Standard diameter shafts accept common inserts, cost less, are more widely stocked, and are more forgiving of small errors in rest setup and centre shot. Micro shafts demand more care in component selection and squaring. For a first set of arrows, standard diameter is usually the practical choice, with micro reserved for long range or larger game builds.
How we choose: we compare published manufacturer specifications, verified owner reviews, and pro shop guidance. We do not test gear in person. Draw weight and arrow spine affect safety, so follow your bow manufacturer's specifications and have setup work checked by a qualified pro shop.