A pawn unit serves a chess engine as a unit of measure for assessing and evaluating a position.

There is a rule of thumb according to which the exchange value of pieces is defined in pawn units:
• Queen = 9 pawn units
• Rook = 5 pawn units
• Bishop = 3 pawn units
• Knight = 3 pawn units
• Pawn = 1 pawn unit
This system only serves as a rough orientation. Positional criteria also enter into a chess engine's evaluation and, depending on the situation, are given as fractions of a pawn unit or significantly higher values.