Accuracy Divide all correct classes by the amount of classes in total. For two classes: ACC=TP+TNTP+FP+FN+TNACC =\frac{TP+TN}{TP+FP+FN+TN}ACC=TP+FP+FN+TNTP+TN However the accuracy may be biased towards a certain class. Thats why other measures have been introduced like Recall and Precision.