What is the speed of an anti-tank missile?

An anti-tank missile is accelerating from the moment the rocket motor is ignited. That means it is going faster and faster at each moment until it strikes its target or runs out of fuel. Most missile systems possess this characteristic, that is, they don't have a cited "top speed" because of the variability of the speed reached based on the distance to target. In the case of just one missile system, the Javelin (and not the surface-to-air one), the missile has a 2,500 metre range, and can get easily achieve mach numbers at longer ranges within its designed reach.