Bolt deals by default 30,000 damage to a unit, which is then reduced by the targeted unit's hack-, pierce-, and crush armor, according to the following formula:
Damage dealt = 30,000 - 10,000*(H+P+C), where H, P, and C are the unit's hack-, pierce-, and crush armor, respectively (in percent). Titans, who are normally (outside of custom scenarios) the only targets capable of surviving a Bolt, are an exception to this rule. When Bolt is used against a Titan, the Titan survives but loses about a third of its hit points.
Though an Archaic Age god power, Bolt is often more useful in later Ages. It is best used on powerful units in which will make an enemy army more vulnerable. It can come in useful early in the game by killing enemy scouts or by taking out Norse infantry which will hinder their ability to build. Alternatively, players can target units limited in number, such as Greek or the Pharaoh. Bolt can also be used to deal with powerful enemy units created by other god powers, particularly Son of Osiris and Nidhogg (except in the Extended Edition, where they only receive 1% and 2% damage respectively). Players can use Bolt against an enemy Titan, but there will still be need for considerable follow-up attacks to kill it.