Value of pieces
Calculations of the value of pieces provide only a rough idea of the state of play. The exact piece values will depend on the game situation.
Edward Lasker said "It is difficult to compare the relative value of different pieces, as so much depends on the peculiarities of the position...". Nevertheless, he said that bishops and knights (minor pieces) were equal, rooks are worth a minor piece plus one or two pawns, and a queen is worth three minor pieces or two rooks (Lasker 1915).
👍 Video - why 3 pieces are better than the queen (6:26)