likert with dimensions calculate range

[royer11]

hello, I am trying to calculate the intervals / categories of a dimension of 4 items / questions

Dimension
Q1 | x | x | x | x |
Q2 | x | x | x | x |
Q3 | x | x | x | x |
Q4 | x | x | x | x |

intervals
4 - x (not satisfied at all)
x - x
x - x
x - 16 (Totally satisfied)

how would you calculate the range?