When you try to run a program in VBA (Visual Basic for Applications), you may suddenly encounter the error message: “Compile error: Duplicate declaration in current scope”.
Whether you are a beginner or an experienced user, this error can be confusing. This article explains the meaning, causes, and solutions for this error in a simple way.
Error Overview: What is “Duplicate declaration in current scope”?
This compile error occurs when you declare a variable, constant, or procedure (Sub or Function) with the same name more than once within the same scope (area of application).
Example: Duplicate Variable Names
Dim i As Long
Dim i As Integer ' <- Error: The same variable name is declared again
Example: Duplicate Procedure Names
Sub ProcessData()
End Sub
Sub ProcessData() ' <- Error: A Sub with the same name already exists
End Sub
Common Causes and Points to Note
| Cause | Description |
| Double Variable Declaration | You defined the same variable name using Dim multiple times within the same function or module. |
| Duplicate Function/Sub | Two or more Subs or Functions with the same name exist in the same module. |
| Name Conflict | A local variable name conflicts with a global variable or property name. |
| External Reference Conflict | Objects or constants with the same name exist across different libraries (e.g., MSForms). |
Solutions
You can resolve the error effectively using the following methods.
1. Do Not Redeclare Variables with the Same Name
Ensure that each variable within a scope has a unique name.
' NG
Dim count As Long
Dim count As Integer ' <- Duplicate
' OK
Dim count As Long
Dim totalCount As Integer
2. Make Subroutine and Function Names Unique
Change the names of your procedures so they do not overlap.
' NG
Sub ExportData()
End Sub
Sub ExportData() ' <- Duplicate Name
' OK
Sub ExportData()
End Sub
Sub ExportDataToCSV()
End Sub
3. Use Option Explicit
By writing Option Explicit at the beginning of your module, you are forced to declare all variables explicitly. This helps prevent accidental redeclarations and spelling mistakes.
Summary: Naming Rules and Organized Code are Key
The “Compile error: Duplicate declaration in current scope” is an error that becomes more likely as your VBA code becomes more complex.
The key to prevention is to avoid using the same name within a single scope and to clearly separate roles for each procedure.
If this error occurs while you are writing code, stay calm and check if any variable or procedure names are duplicated.
