What are you trying to achieve? If you are trying to do something fancy with a Cobol record-layout, you have a lot of work ahead of you.
How long are these?
05 A-CHARACTER PIC X.
05 A-BINARY-EX1 COMP PIC 9.
05 A-BINARY-EX2 COMP PIC 9(5).
05 A-COMP3-EX1 COMP-3 PIC 9(5).
05 A-COMP3-EX2 COMP-3 PIC 9(4).
05 A-COMP3-EX3 COMP-3 PIC 9(5)V9(4).
05 A-FLOAT COMP-1
05 A-BIGGER-FLOAT COMP-2
05 A-FIELD-WHICH-IS-EDITED PIC X(8)BX(8).
And how long is the record?
That is without 66s, 77s, 88s, OCCURS, REDEFINES (including the possibility of redefining longer
than the original field), indexes etc.
If you can get your answer from a Compile listing, the Compiler will have done the hard work for you.