The paper dealt with prediction of the 28-day compressive strength of cement by using a rapid method of determining the early heat of hydration. The early heat of hydration and the standard strength of cement being determined on a number of cements may serve for establishing a correlation to predict the 28-day strength. The relation needs validation on a greater number of cements of the same type and manufacturer. The investigations involved the following steps: i) determining the standard strength as per SR EN 196–1, ii) determining the early heat of hydration by using a calorimeter enhanced with 1-minute incremental temperature monitoring software, iii) establishing a correlation equation, and iv) validating the correlation on 70 cements CEM II/A and B–S. The rapid estimation of the 28-day strength of cement CEM II/A and B–S with a precision of ±2.5 MPa is a versatile tool in cement manufacture. The same algorithm may be applied and validated for any cement sort.