Ratio between the mass predicted by the CNN+MAF model and the true mass enclosed within different radii of the galaxies in the training and validation sets of NIHAO (left panel) and AURIGA (right panel) datasets. The blue line shows the median ratio determined using the mass estimated by the CNN+MAF for the training set, while the shadowed region indicates the 1σ dispersion. The pink line and shadowed region correspond to CNN+MAF predictions for the validation set. The predicted versus true mass ratios resulting from applying literature mass estimators to either NIHAO (left panel) or AURIGA (right panel) galaxies are shown as grey symbols with 1σ error bars.