How To Convert a Fraction to a Decimal Number (185424)



The information in this article applies to:

  • Microsoft Visual Basic for Applications 5.0

This article was previously published under Q185424

SUMMARY

This article provides a routine to convert a string that contains a fraction in the form "a," "a/b," or "a b/c" into a double precision floating-point number.

MORE INFORMATION

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  1. Create a new Visual Basic for Applications project and add the following code to a module:

    Sample Code

          Function Frac2Num(ByVal X As String) As Double
          Dim P As Integer, N As Double, Num As Double, Den As Double
             X = Trim$(X)
             P = InStr(X, "/")
             If P = 0 Then
                N = Val(X)
             Else
                Den = Val(Mid$(X, P + 1))
                If Den = 0 Then Error 11    ' Divide by zero
                X = Trim$(Left$(X, P - 1))
                P = InStr(X, " ")
                If P = 0 Then
                   Num = Val(X)
                Else
                   Num = Val(Mid$(X, P + 1))
                   N = Val(Left$(X, P - 1))
                End If
             End If
             If Den <> 0 Then
                N = N + Num / Den
             End If
             Frac2Num = N
          End Function
    						
  2. In the Debug/Immediate window, test:

    ? Frac2Num("5 3/4"), Frac2Num("2/8")

    Result: 5.75 0.25
Note: Numbers in the input string do not have to be whole numbers. They can contain decimal values and negative numbers.

REFERENCES

For more information about getting help with Visual Basic for Applications, please see the following article in the Microsoft Knowledge Base:

163435 VBA: Programming Resources for Visual Basic for Applications


Modification Type:MajorLast Reviewed:6/23/2005
Keywords:kbhowto KB185424