FER2013 stands for Facial Expression Recognition 2013 Dataset. This dataset contains approximately 30,000 facial RGB images with different expressions. The image size is 48×48 pixels.

The main annotations in this dataset can be divided into 7 types: 0 = Angry, 1 = Disgusted, 2 = Fearful, 3 = Happy, 4 = Sad, 5 = Surprised, 6 = Neutral. Disgusted expressions have the least number of images, only 600, while each of the other types has nearly 5,000 samples.