Broadhead Penetration Calculator

Estimated Penetration is calculated purely from Momentum, Broadhead Type, and Cut Diameter — Kinetic Energy has no mathematical connection to it in this model, reflecting the view among many bowhunting researchers that momentum predicts penetration better than kinetic energy does. Kinetic Energy only feeds into the separate Adequate for Deer check alongside the 8-inch penetration threshold.

Yes, in this model — Cut Diameter divides directly into the penetration formula, so a broadhead with a 2-inch cutting diameter is estimated to penetrate roughly half as deep as one with a 1-inch cut, all else equal. This mirrors the real bowhunting trade-off that many hunters weigh between a wider mechanical or wide fixed blade and the deeper penetration typically associated with narrower fixed blades.

Barely, in this model — despite Estimated Penetration dropping substantially as Cut Diameter increases, Wound Channel Area (pi × Cut Diameter × Estimated Penetration) stays almost perfectly flat, changing by well under 1% across the full Cut Diameter range. That's a direct mathematical consequence of penetration being modeled as roughly inversely proportional to Cut Diameter: the wider-but-shallower cylinder and the narrower-but-deeper cylinder work out to nearly the same total surface area. Don't use Wound Channel Area to compare "bigger wound channel" trade-offs between broadhead widths — use Estimated Penetration for that comparison instead; Wound Channel Area is better read as a rough total-surface-area estimate for a single setup, not a comparison tool across Cut Diameter choices.

Easton's published kinetic-energy chart lists 25-41 ft-lbs as the range for medium game such as deer, so 25 sits at the bottom of that range rather than in the middle of it. Many bowhunters and several state hunter-education programs recommend aiming for 40+ ft-lbs for a more reliable pass-through, especially on a quartering or less-than-ideal shot, rather than treating the 25 ft-lbs floor as a comfortable target.

It does not model front-of-center (FOC) balance, arrow spine or flex during flight, shot angle, or the real variation in hide, muscle, and bone density between individual animals — all of which affect real-world penetration. Treat the Estimated Penetration figure as a rough planning number for comparing setups, not a guarantee of an ethical, lethal shot in the field.