High-explosive anti-tank (HEAT) is the effect of a shaped charge explosive that uses the Munroe effect to penetrate heavy armor. The warhead functions by having an explosive charge collapse a metal liner inside the warhead into a high-velocity shaped charge jet; this is capable of penetrating armor steel to a depth of seven or more times the diameter of the charge (charge diameters, CD). The shaped charge jet armor penetration effect is purely kinetic in nature; the round has no explosive or incendiary effect on the armor.

As they rely on the kinetic energy of the explosively formed jet (EFP) for their penetration performance, HEAT warheads do not have to be delivered with high velocity, as an armor-piercing round does. Thus they can be fired by lower-powered weapons that generate less recoil.

The performance of HEAT weapons has nothing to do with thermal effects, with HEAT being simply an acronym.