This is pretty simple, I'll be calculating the weight of a metal plate Izuku carries during the race.
Scan 1
Izuku Height = 166 cm (179 px)
Metal Plate Depth = 6.49162011173 cm (7 px)
Scan 2
Metal Plate Surface Area = 16628.7486034 cm^2 (17931 pixel square) Look towards the blue arrow.
Volume = 16628.7486034 x 6.49162011173 = 107947.518867 cm^3
Steel Density = 8.05 g/cm^3
Metal Plate Weight = 107947.518867 x 8.05 = 868977.526879 grams, 868.97 kg (Class 1)