Count based on another column

hello misul,

You could try:

Column = 
CALCULATE(
   DISTINCTCOUNT(Table1[Route]),
   ALLEXCEPT(Table1,Table1[Customer])
   )

ChrisMendoza Correct, the intention is to use DistinctCountofRoutes as a slicer.

When I use the calculated column, the values are summed. So I put the column to "Don't Summarize" and it seems to work now. Thanks!

Calculated Column: 

Column = 
CALCULATE(
   DISTINCTCOUNT(Table1[Route]),
   ALLEXCEPT(Table1,Table1[Customer])
   )

Measure:

Measure= 
CALCULATE(
   DISTINCTCOUNT(Table1[Route]),
   ALLEXCEPT(Table1,Table1[Customer])
   )

I realised that the same formula can be used as a measure too. But as measures cannot be used in Slicers. I will stick with Calculated Column (without summarizing it).