🏹 Bow IBO Speed Calculator
Find your real arrow speed based on your actual draw length, weight, and arrow setup
| Factor | IBO Standard | Adjustment Per Unit | Direction |
|---|---|---|---|
| Draw Length | 30 inches | +/- 10 fps per inch | Below 30" = subtract; above = add |
| Draw Weight | 70 lbs | +/- 2 fps per lb | Below 70 lbs = subtract; above = add |
| Arrow Weight | 350 grains | +/- 1 fps per 3 grains | Over 350 gr = subtract; under = add |
| String Accessories | None | -1 fps per 3 grains | Any string mass = subtract |
| KE Range (ft-lbs) | Recommended Game | Hunting Suitability |
|---|---|---|
| Under 25 | Small Game, Turkey | Minimum for turkeys; light small game |
| 25 - 41 | Whitetail Deer | Adequate for deer at close range |
| 42 - 65 | Elk, Black Bear | Good for large deer and elk |
| 65+ | Large / Dangerous Game | Suitable for moose, cape buffalo, large bear |
| Arrow Weight (grains) | vs 350 gr Baseline | Approx Speed Change | Effect |
|---|---|---|---|
| 275 grains | -75 grains lighter | +25 fps | Fastest, flattest trajectory, least KE |
| 300 grains | -50 grains lighter | +17 fps | Speed-oriented, competition target |
| 350 grains | IBO baseline | 0 fps | Standard reference |
| 400 grains | +50 grains heavier | -17 fps | Good balance, deer/elk hunting |
| 450 grains | +100 grains heavier | -33 fps | High penetration, big game |
| 500 grains | +150 grains heavier | -50 fps | Maximum penetration, heavy game |
IBO stands for the International Bowhunters Organization. You often see this term when you buy bows or read about archery gear. So that one can easily compare different bows, the IBO made a regular way to measure the speed of the shot arrows.
Basically, that measures the power of the bow
What IBO Bow Speed Means
One finds the IBO speed shooting an arrow through a chronograph under very precise conditions. The bow must have draw weight of 70 pounds and draw length of 30 inches, using an arrow of 350 grains. Other test parameters use draw weight of 80 pounds (with a tolerance of 2 pounds), max draw length and 400-grain arrow.
The weight of the arrow is 5 grains for every pound of draw weight. For instance, for a bow of 60 pounds, the IBO arrow would be 300 grains.
There is also the ATA, that stands for the Archery Trade Association. The IBO and the ATA have their own methods for estimating the speed, and some companies prefer one over the other. Although the methods differ, both serve to compare the relative pace of the gear.
Here where things become complex. The IBO rating considers every possible advantage. If someone shoots with 30-inch length and 350-grain arrow, but adds a D loop, silencers and fletched arrows, most bows indeed will shoot slower than the advertised IBO value.
For every 3 grains of total arrow weight above the standard calculation (draw weight x 5), one must reduce 1 foot each second from the IBO value. Moreover, every 3 grains of extra weight on the string remove another 1 foot each second.
Some bows with similar weights have similar IBO values, but certain models are seen as better than others, even if they do not have the highest numbers. That happens because some can push a heavy arrow more effectively, what the bare IBO speed not always shows.
It is worth noting that recurve bows do not have a standard measure like IBO. This system relates mostly to compound bows. Some recurve shooters find that bothering, because speed is described only by means of draw weight without a clear standard.
Some archers noticed that modern bows do not always show big improvements in speed compared with old models. For instance, a bow from 2013 could have technical data like to new, costly choices. A bow as the Hoyt Ventum 33 was listed with 334 feet each second IBO and cost around 1,200 dollars for the barebow.
