Momentum is a passive effect in the game Baldurs Gate 3 that increases a characters movement speed by a certain amount. The amount of increase depends on the item that grants Momentum and the number of turns remaining on the effect. For example, the Spurred Band ring grants a 1.5-meter increase in movement speed, while the Boots of Striding grant Momentum when casting a spell that requires concentration. The effect of Momentum is removed when the character becomes Restrained, Prone, or Incapacitated.

Momentum is a useful status condition that can help characters move further and reach targets that would otherwise be out of reach. It is typically gained from the effects of equipped magic items, such as weapons, armor, and accessories. Players can create a team of fast-moving speed demons by equipping items that grant Momentum, such as the Springstep Boots or the Haste Helm.

In summary, Momentum is a passive effect in Baldurs Gate 3 that increases a characters movement speed by a certain amount, depending on the item that grants it. It is a useful status condition that can help characters move further and reach targets that would otherwise be out of reach.