Returns the number of repetitions of the repeating field fieldName as it is currently formatted on layoutName (which could be different from the number of repetitions when the field was defined), and the orientation of the field repetitions (horizontal or vertical) on the layout.
fileName - the name of an open database file (local or remote).
layoutName - the name of a layout in the specified database file.
fieldName - the name of a field on the specified layout.
Important  See Design functions for information about literal text parameters.
Data type returned 
Originated in 
FileMaker Pro 6.0 or earlier
If fieldName isn’t a repeating field, it returns 1 vertical.
FieldRepetitions(“Customers”;“Data Entry”;“Business Phone”) returns 3 vertical if the Business Phone field is defined as a repeating field with five repetitions but is formatted to only show three repetitions in a vertical orientation on the Data Entry layout.
Related topics 
Functions reference (category list)
Functions reference (alphabetical list)
About formulas
About functions
Defining calculation fields
Using operators in formulas