How to Create Bins for Calculated Fields

Possible workarounds are as below.

Option 1: Use level of detail (LOD) calculations to create bins. For more information, see : Create Level of Detail Expressions in Tableau

For example, 

{FIXED Region:

IF  [field name] <1 THEN "bin 1"

ELSEIF [field name] >=1 THEN "bin 2"

END}

Option 2:  Create bins using an IF/THEN calculation. For more information, see Logical Functions > IF test1 THEN value1 ELSEIF test2 THEN value2 ELSE else END > Example. 

For example:

IF [field name] <1 THEN "bin 1"

ELSEIF  [field name] >=1 THEN"bin 2"

END

Option 3. Manually Create a binning calculation

For example,

INT([field name]/[Bin Size])*[Bin Size]