What is a contract’s tick size?

A “tick size” refers to the minimum price movement by which a specific contract can change. Tick values vary depending on the type of contract. For example, the tick size for the E-mini S&P 500 is 0.25 points. Since each E-mini S&P 500 contract represents 50 times the S&P 500 Index, every 0.25-point move in the E-mini S&P 500 is equivalent to USD 12.50.