In chemistry, the endpoint is a term used in titration, which is a technique used in analytical chemistry to determine the concentration of unknown solutions by using a solution of known concentration. During titration, the endpoint is the point at which the solution changes color due to the addition of a titrant, indicating the completion of the reaction. The endpoint is not the same as the equivalence point, which is the point at which the added titrant is chemically equivalent to the analyte in the sample. The difference between the endpoint and the equivalence point is known as the titration error, which is kept as small as possible. The endpoint is used as an approximation of the equivalence point and is employed, with the known concentration of the titrant, to calculate the amount or concentration of the analyte.