A simple graphical method for determining enzyme inhibitor constants is described. The Michaelis constant, $ K_m $, is determined by plotting 1/v against 1/s, allowing the Michaelis equation to be represented as a straight line. The inhibitor constant, $ K_i $, is determined by plotting 1/v against i at two different substrate concentrations, with the lines intersecting at a point giving $ -K_i $. This method is applicable for competitive inhibition. For non-competitive inhibition, the lines intersect the baseline at a point giving $ -K_i $. The method is straightforward and provides a direct way to determine these constants without complex calculations. The approach is based on the reciprocal forms of the Michaelis-Menten equation and the modified equation for competitive inhibition. The graphical method is more efficient and accurate than previous methods, and it allows for the determination of both $ K_m $ and $ K_i $ from the same data. The method is applicable to a wide range of enzyme-inhibitor systems and provides a reliable way to determine the equilibrium constants for enzyme-substrate and enzyme-inhibitor interactions. The work builds on previous studies by Dixon (1949) and others, and it provides a new and simpler method for determining these constants. The method is particularly useful for enzyme systems where the inhibitor is competitive, and it allows for the determination of $ K_i $ from a single substrate concentration. The method is also applicable to non-competitive inhibition, where the lines intersect the baseline at a point giving $ -K_i $. The method is simple, efficient, and accurate, and it provides a reliable way to determine the equilibrium constants for enzyme-inhibitor interactions.A simple graphical method for determining enzyme inhibitor constants is described. The Michaelis constant, $ K_m $, is determined by plotting 1/v against 1/s, allowing the Michaelis equation to be represented as a straight line. The inhibitor constant, $ K_i $, is determined by plotting 1/v against i at two different substrate concentrations, with the lines intersecting at a point giving $ -K_i $. This method is applicable for competitive inhibition. For non-competitive inhibition, the lines intersect the baseline at a point giving $ -K_i $. The method is straightforward and provides a direct way to determine these constants without complex calculations. The approach is based on the reciprocal forms of the Michaelis-Menten equation and the modified equation for competitive inhibition. The graphical method is more efficient and accurate than previous methods, and it allows for the determination of both $ K_m $ and $ K_i $ from the same data. The method is applicable to a wide range of enzyme-inhibitor systems and provides a reliable way to determine the equilibrium constants for enzyme-substrate and enzyme-inhibitor interactions. The work builds on previous studies by Dixon (1949) and others, and it provides a new and simpler method for determining these constants. The method is particularly useful for enzyme systems where the inhibitor is competitive, and it allows for the determination of $ K_i $ from a single substrate concentration. The method is also applicable to non-competitive inhibition, where the lines intersect the baseline at a point giving $ -K_i $. The method is simple, efficient, and accurate, and it provides a reliable way to determine the equilibrium constants for enzyme-inhibitor interactions.