Kinetic Energy by Game Chart: KE and Momentum
Commonly cited kinetic energy ranges are under 25 foot-pounds for small game, 25 to 41 for deer sized animals, 42 to 65 for elk and black bear, and 65 or more for moose, bison and the largest animals. Momentum guidance runs from about 0.40 slug-feet per second for deer to 0.85 and up for the heaviest game.
Kinetic energy is the number archers reach for when they ask whether a setup is enough. It is a useful screening figure and a poor stopping point, because momentum predicts penetration through resistance better than energy does. The chart below gives both, alongside the arrow weights people typically build to for each animal.
Kinetic energy and momentum by animal
These are the ranges commonly published by broadhead and shaft manufacturers, hunter education materials and outfitters. They are guidance, not law and not guarantees. Shot placement, broadhead sharpness and arrow construction all outweigh a handful of foot-pounds.
| Animal | Commonly cited KE | Commonly cited momentum | Typical arrow weight | Notes |
|---|---|---|---|---|
| Small game (rabbit, squirrel) | under 25 ft-lb | under 0.30 | 300-400 gr | Blunts and small game heads, not broadheads |
| Upland birds | under 25 ft-lb | under 0.30 | 300-400 gr | Judo and flu-flu setups, short range |
| Wild turkey | 25-40 ft-lb | 0.35-0.45 | 375-450 gr | Wide cutting heads are the usual choice |
| Bowfishing (carp, gar) | not the governing factor | n/a | 1,000+ gr | Heavy fibreglass arrow, very short range, refraction dominates |
| Javelina | 25-35 ft-lb | 0.35-0.45 | 375-450 gr | Small bodied, thin skinned |
| Pronghorn antelope | 25-40 ft-lb | 0.38-0.48 | 375-450 gr | Light framed, often long open-country shots |
| Whitetail deer | 25-41 ft-lb | 0.40-0.50 | 400-475 gr | Cleared by nearly any modern compound |
| Blacktail deer | 25-41 ft-lb | 0.40-0.50 | 400-475 gr | Similar build to whitetail |
| Mule deer | 30-45 ft-lb | 0.42-0.52 | 420-500 gr | Heavier framed than whitetail |
| Feral hog | 40-55 ft-lb | 0.50-0.60 | 450-550 gr | Shoulder shield on mature boars favours momentum |
| Black bear | 40-55 ft-lb | 0.50-0.60 | 450-550 gr | Dense hair and fat, structural heads preferred |
| Caribou | 40-55 ft-lb | 0.50-0.60 | 450-550 gr | Deer sized frame, often taken at distance |
| Sheep and mountain goat | 40-55 ft-lb | 0.50-0.60 | 450-550 gr | Steep angles make range estimation the harder problem |
| Alligator | 50-65 ft-lb | 0.55-0.70 | 500-650 gr | Specialised regulations and equipment in most states |
| Elk | 42-65 ft-lb | 0.55-0.65 | 450-550 gr | Heavy shoulder bone, arrow build matters as much as KE |
| African plains game, small (impala, warthog) | 40-55 ft-lb | 0.50-0.60 | 450-550 gr | Outfitters often set their own equipment minimums |
| African plains game, large (kudu, zebra, wildebeest) | 60-80 ft-lb | 0.65-0.80 | 550-700 gr | Heavy hide and dense bone |
| Moose | 65 ft-lb and up | 0.65-0.75 | 500-650 gr | Large body cavity, deep penetration required |
| Bison | 65 ft-lb and up | 0.70-0.85 | 600-750 gr | Heavy arrows and single-bevel heads are the norm |
| Brown or grizzly bear | 65 ft-lb and up | 0.70-0.85 | 600-750 gr | Guided hunts commonly set equipment minimums |
| Cape buffalo | 80 ft-lb and up | 0.85 and up | 750-950 gr | Extreme FOC and heavy single-bevel heads are standard |
Ranges vary between sources and some outfitters and countries set their own binding equipment minimums. Where a published figure and an outfitter requirement disagree, the outfitter requirement is the one that decides whether you hunt.
The two formulas, and why they disagree
Kinetic energy in foot-pounds equals arrow weight in grains multiplied by velocity in feet per second squared, divided by 450,240. The constant folds together the 7,000 grains in a pound and the gravity conversion, so you can work in the units printed on your arrow packaging.
Momentum equals arrow weight in grains multiplied by velocity, divided by 225,218, expressed in slug-feet per second. The structural difference is the exponent. Energy squares velocity, so speed is worth more than mass to it. Momentum treats the two equally, so mass counts fully. Two archers can therefore look at the same arrow and honestly reach opposite conclusions, depending on which measure they were taught to trust.
Where energy peaks and momentum keeps climbing
This table takes one bow and changes only arrow weight. The baseline is a setup that chronographs 400 grains at 280 fps, and speeds for the other weights use the standard approximation of about 1 fps lost per 3 grains added. Watch the two right-hand columns move in different directions.
| Arrow weight | Estimated speed | Kinetic energy | Momentum | gr/lb at 70 lb |
|---|---|---|---|---|
| 350 gr | 297 fps | 68.6 ft-lb | 0.462 | 5.0 |
| 400 gr | 280 fps | 69.7 ft-lb | 0.497 | 5.7 |
| 425 gr | 272 fps | 69.8 ft-lb | 0.513 | 6.1 |
| 450 gr | 263 fps | 69.1 ft-lb | 0.525 | 6.4 |
| 475 gr | 255 fps | 68.6 ft-lb | 0.538 | 6.8 |
| 500 gr | 247 fps | 67.8 ft-lb | 0.548 | 7.1 |
| 550 gr | 230 fps | 64.6 ft-lb | 0.562 | 7.9 |
| 600 gr | 213 fps | 60.5 ft-lb | 0.567 | 8.6 |
| 650 gr | 197 fps | 56.0 ft-lb | 0.569 | 9.3 |
| 700 gr | 180 fps | 50.4 ft-lb | 0.559 | 10.0 |
The 1 fps per 3 grains rule is a linear approximation and it overstates the loss at the heavy end, so a real chronograph usually shows heavy arrows doing better than this table suggests. The shape of the two curves is the point, not the third decimal place.
Read down the energy column and it rises, flattens near 425 grains, then falls. Read down the momentum column and it rises the whole way before flattening past 600 grains. If you optimise for energy you land near 425 to 450 grains. If you optimise for momentum you land far heavier. Neither is wrong, and both are why the honest answer to how heavy an arrow should be is a range, not a number.
How to use these figures without over-reading them
Use the chart as a floor check, not a target. If your setup produces 70 foot-pounds and 0.50 momentum, you have cleared the commonly cited deer band several times over, and the next foot-pound buys you very little. Effort spent on broadhead sharpness, arrow flight and honest distance limits buys far more.
The place these numbers earn their keep is at the edges. A youth or lower poundage setup, a very short draw length, or an animal genuinely larger than deer are all situations where the arithmetic can tell you something you would otherwise guess at. Run yours through the kinetic energy calculator, which returns momentum alongside energy and flags the 5 grain per pound safety floor.
What matters more than the number
Arrow flight. A fixed broadhead on a poorly tuned arrow bleeds energy to drag and steers badly the moment it meets resistance. A tuned 55 foot-pound setup outperforms an untuned 75 foot-pound one. Work through the tuning troubleshooting chart before chasing weight or speed.
Broadhead sharpness and construction. Cutting efficiency is the difference between energy spent making a hole and energy spent pushing tissue aside. A dull head or a weak ferrule wastes whatever the chronograph says.
Front of centre. Weight distribution changes how an arrow behaves on impact, not just in flight. Hunting builds typically target 10 to 15 percent, and higher figures are common on large animals. The FOC reference chart covers the bands and what each is used for.
Distance discipline. Misjudging distance causes far more poor hits than a marginal setup does. Energy figures only mean anything at a known range, and every foot-pound in the table assumes the arrow arrives where it was aimed.
Safety note that applies to every row above: the finished arrow must weigh at least 5 grains per pound of draw weight, and draw weight itself should be a weight you can draw under control, seated and cold, without skyward-pointing. Have setup work checked by a qualified pro shop.
Related tools and charts
- Arrow kinetic energy calculator: KE and momentum for your exact setup
- Total arrow weight calculator: build the grain figure this chart needs
- Arrow speed calculator: real fps from an IBO rating
- Arrow weight chart: GPI and finished weight examples
- Bowhunting draw weight minimums by state: the rules that actually bind
Frequently asked questions
How much kinetic energy do I need for whitetail deer?
The range cited by manufacturers and most state guidance is roughly 25 to 41 foot-pounds for deer sized game. Nearly any modern compound clears that comfortably: a 400 grain arrow at 260 fps already produces about 60 foot-pounds. Because the floor is so easy to clear, energy is rarely the limiting factor on deer. Broadhead sharpness, arrow flight and shot placement decide outcomes far more often.
Is kinetic energy or momentum more important for penetration?
Momentum tracks penetration through resistance more closely, which is why heavy arrow advocates cite it. Kinetic energy scales with the square of velocity, so it rewards light fast arrows, while momentum scales linearly with both mass and velocity, so it rewards mass. A setup can look strong on one measure and ordinary on the other. Read both, and weight momentum more heavily as the animal gets larger.
What is a good kinetic energy for elk?
Commonly cited figures put elk in the 42 to 65 foot-pound range, with momentum around 0.55 to 0.65 slug-feet per second. Most elk hunters build toward 450 to 550 grains finished, which lands in that band from a normal 60 to 70 lb bow. Arrow construction matters as much as the number: a strong shaft, a solid insert and a durable single-bevel or cut-on-contact head do more than a few extra foot-pounds.
Can a 40 lb bow generate enough energy to hunt deer?
Often yes, and many states permit it. A 40 lb bow with a 27 inch draw and a 400 grain arrow typically produces somewhere near 30 to 40 foot-pounds, which sits inside the commonly cited deer range. What it will not do is forgive marginal shots or heavy bone. Lower poundage setups demand a heavier arrow for its weight class, a very sharp cut-on-contact head, and shorter self-imposed distance limits.
Does a heavier arrow always increase kinetic energy?
No. Adding weight also lowers velocity, and because kinetic energy squares velocity, energy peaks and then falls as arrows get very heavy. Momentum keeps rising and then flattens. On a typical setup, energy peaks somewhere near 425 to 450 grains while momentum keeps climbing past 600. That is the whole heavy versus light argument in one sentence, and it is why the two camps both have arithmetic on their side.
Are these kinetic energy figures legal minimums?
Almost never. Very few states legislate arrow energy, and those that regulate archery equipment usually do it through minimum draw weight, minimum arrow weight, minimum arrow length and broadhead width instead. Treat the figures on this page as widely published guidance rather than law, and check your state agency for the requirements that actually bind you before a season.
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.