The pieces have point-values which reflect their degree of mobility.
However, the position on the board can affect the mobility and roles of the pieces – therefore the points are only an estimation of their value in average situations.
The piece value chart below show the value of the most powerful chess pieces in order from lowest to highest:
* In most positions a bishop is actually worth a bit more than a knight
** The king is a powerful piece in the endgame-stage of the game
An advantage refers to any factors in the position that may improve your chances of winning the game.
A material advantage goes to the player who has more and/or stronger pieces. The simplest way to determine which player has a material advantage is to compare the point-values of the remaining pieces on the board.
Material superiority isn’t the only factor that determines who has an advantage, but it is often the most important one.