XL: "Overflow" Error Running Procedure with Math Calculation

• Microsoft Excel for Windows, versions 5.0, 5.0c
• Microsoft Excel for the Macintosh, versions 5.0, 5.0a
• Microsoft Excel for Windows 95, versions 7.0, 7.0a
• Microsoft Excel 97 for Windows
• Microsoft Excel 98 Macintosh Edition

SYMPTOMS

In Microsoft Excel, when you run a Microsoft Visual Basic for Applications procedure that contains a mathematical calculation, you may receive the following error message:

   Run-time error '6':
   Overflow

CAUSE

This error message appears when the mathematical calculation involves numbers or variables of one data type, such as Integer, and you assign the result of the calculation to a variable of a different data type, such as Double or Long, even if the result of the calculation is within the range of the data type for the resulting variable. For example, you receive this error message when you run the following procedure:

   Sub Test()
       Dim MyVarInteger As Integer
       Dim MyVarDouble As Double
       MyVarInteger = 256
       MyVarDouble = 256 * MyVarInteger
   End Sub

By declaring the result, MyVarDouble, as Double data type, the calculation multiplies the two Integer data types and then attempts to convert the result to a Double data type. Because the result is not within the range for an Integer data type, the error occurs before the result is converted to the Double data type.

You also receive this error message when you run the following procedure:

   Sub Test2()
       x = (3832908 * 1000) / (2 * 218706)
       MsgBox x
   End Sub

WORKAROUND

Microsoft provides programming examples for illustration only, without warranty either expressed or implied, including, but not limited to, the implied warranties of merchantability and/or fitness for a particular purpose. This article assumes that you are familiar with the programming language being demonstrated and the tools used to create and debug procedures. Microsoft support engineers can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific needs. If you have limited programming experience, you may want to contact the Microsoft fee-based consulting line at (800) 936-5200. For more information about the support options available from Microsoft, please see the following page on the World Wide Web:

   http://www.microsoft.com/support/supportnet/refguide/default.asp

Method 1

Use a data type conversion function, such as CLng in the following example:

   Sub Test()
      Dim MyVarInteger As Integer
      Dim MyVarDouble As Double
      MyVarInteger = 256
      ' Use CLng function to convert MyVarInteger to Long data type.
      MyVarDouble = 256 * CLng(MyVarInteger)
   End Sub

Method 2

Use a type-declaration character as in the following examples:

   Sub Test()
      Dim MyVarInteger As Integer
      Dim MyVarDouble As Double
      MyVarInteger = 256
      ' Follow 256 with an ampersand to identify value as Long data type.
      MyVarDouble = 256& * MyVarInteger
   End Sub

   Sub Test2()
      ' Follow 1000 with number sign to identify value as Double data type.
      x = (3832908 * 1000#) / (2 * 218706)
      MsgBox x
   End Sub

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

The Help topic for this error message indicates that a possible cause for this error message includes the following:

   The result of an assignment, calculation, or data type conversion is too
   large to be represented within the range allowed for that type of
   variable.

REFERENCES

For a Data Type Summary, choose the Search button in the Visual Basic Reference and type:

   data types