APFSDS Penetration Calculator

Based on the calculator by Willi Odermatt. Uses the lower estimate from the APFSDS table.

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Penetrator

Mode iPerforation — the penetrator punches completely through a finite armor plate. Calculates the maximum plate thickness that can be defeated at the given obliquity and velocity.

Penetration — the penetrator embeds into a semi-infinite (unbacked) target. Returns maximum depth reached. Obliquity is ignored. Valid for Tungsten only.

Material iTungsten (WHA) — Tungsten Heavy Alloy, density ~17,000–19,300 kg/m³. Standard for modern APFSDS. Supported in both Perforation and Penetration modes.

DU — Depleted Uranium, similar density to tungsten but exhibits adiabatic shear ("self-sharpening"), giving slightly deeper penetration per unit length. Perforation only.

Steel — lower density (~7,700–8,500 kg/m³), used in older or economical penetrators. Requires penetrator BHN. Perforation only.

Total length mmiFull length of the penetrator rod including the frustum tip (L). Together with the diameter this defines the L/D aspect ratio, which must be ≥ 4 for the model to be valid.

Diameter mmiOuter diameter of the cylindrical rod body (D). Modern APFSDS rounds typically range from 20–30 mm.

Frustum length mmiLength of the tapered tip (frustum) at the front of the penetrator. This section transitions from the full rod diameter down to the tip diameter (field 4).

Frustum upper diameter mmiDiameter at the very tip of the frustum (the narrow end). Must be ≤ the rod diameter. Affects the calculated working length used in the penetration formula.

Density kg/m³iMass per unit volume of the penetrator material. Tungsten: 17,000–19,300 · DU: 16,500–19,100 · Steel: 7,700–8,500 kg/m³. Higher density generally improves penetration.

Impact velocity km/siVelocity of the penetrator at the moment it strikes the target. Must exceed the minimum eroding velocity for the model to be valid (typically ~1.0–1.4 km/s depending on material). Modern APFSDS rounds: 1.5–1.8 km/s.

Target

Density kg/m³iDensity of the target armor plate. Must be in the range 7,700–8,000 kg/m³ (rolled homogeneous steel). Values outside this range are not supported by the Lanz-Odermatt model.

Brinell Hardness BHNiHardness of the target armor. Harder steel resists penetration more effectively. Valid range: 150–500 BHN for Tungsten/DU, 120–550 for Steel penetrators. Typical RHA armor: 250–350 BHN.

NATO obliquity ° — perforation only, max 75°iAngle between the projectile's line of flight and the normal to the target surface. 0° = perpendicular (no slope), 60° = highly sloped armor. Higher obliquity increases effective thickness and can cause ricochet. Not used in Penetration mode.

Diagram

Results

Projectile mass9.79kg

Kinetic energy14.76MJ