At what distance does a bullet stop penetrating a given material? Every other calculator answers how fast the bullet is, or whether it defeats a barrier at the muzzle. This one solves for the distance where the answer changes.
Optional — or set the four numbers below by hand.
The furthest distance at which the bullet still defeats the stated thickness of that material. Past it the bullet still arrives — it simply no longer gets through. That is a different question from the usual effective-range figure, which is about accuracy or a minimum energy threshold.
Because both happen. A single sheet of drywall is too thin to stop a rifle bullet at any distance a rifle is used at, and a 9 mm does not defeat an AR500 plate even at the muzzle. A tool that only ever printed a number would be hiding those two answers.
No — one layer. That also means a hollow point is treated as expanding on contact, rather than clogging in a first layer and continuing like an FMJ. For stacked barriers use the penetration calculator, which models the layers in order.
The velocity at each distance comes from the trajectory model, which integrates G1 drag and knows about the transonic region. The penetration at that velocity comes from the material’s own model — Poncelet, Johnson–Cook, orthotropic, Mohr–Coulomb or a fibre model, depending on what is being shot. Both run on the server; this page sends one request and draws the answer.