Normalization

The few degrees a shell turns toward the perpendicular on impact, reducing the effective armor it has to cross.

Also known as shell normalisation, normalisation, shell normalization, two caliber rule.

On contact the shell rotates slightly into the plate before penetrating, which shortens its path through the steel. Armor-piercing and high explosive shells normalize by five degrees, APCR by two, HEAT not at all.

This is why APCR is worse against sloped armor than its raw penetration suggests, and why a HEAT shell has to defeat the full effective thickness of a steep plate.

Large shells against thin plates get considerably more of it: past roughly twice the plate thickness the normalization bonus scales up with caliber, which is what makes big guns so effective against light armor at an angle.

Related terms

Effective armorThe thickness a shell actually has to defeat once the angle of the plate is accounted for, which is what penetration is compared against.OvermatchThe rule that a shell with a caliber at least three times a plate's thickness cannot ricochet off it, no matter the angle.Armor-piercingThe standard solid shell: reliable damage, moderate penetration, five degrees of normalization and a ricochet beyond 70 degrees.APCRA lighter, faster shell with higher penetration than AP, less normalization and a steeper penetration loss over distance.HEATA shaped-charge shell with high penetration that ignores distance entirely, but is defeated by tracks, screens and any spaced armor it detonates on.

Every World of Tanks term