The use of scale is not uniform and can deviate by as much as 30%. A manufacturer might advertise its figures as 28 mm, but their products may be over 30 mm tall. A contributing factor is the difference in methods used to calculate scale. Some manufacturers measure figure height from the feet to the eyes rather than the top of the head; therefore, a figure in 28 mm scale would be 30 mm tall. As a result, 15 mm figures can be variously interpreted as 1:100 scale or 1:120.