ACC: How to Round a Number Up or Down by a Desired Increment

ID: Q155696

The information in this article applies to:

Microsoft Access versions 1.0, 1.1, 2.0, 7.0, 97

SUMMARY

Moderate: Requires basic macro, coding, and interoperability skills.

This article shows you how to create a procedure that rounds a number up or down by a specified increment. For example, given the number 3.23, rounding to the nearest .05 results in the number 3.25. The procedure in this article accepts any positive rounding increment as a parameter. In addition to rounding numbers to the nearest fractional amount, you can also round to whole numbers, such as 1, 10, or 100.

This article assumes that you are familiar with Visual Basic for Applications and with creating Microsoft Access applications using the programming tools provided with Microsoft Access. For more information about Visual Basic for Applications, please refer to your version of the "Building Applications with Microsoft Access" manual.

NOTE: Visual Basic for Applications is called Access Basic in Microsoft Access versions 1.x and 2.0. For more information about Access Basic, please refer to the "Introduction to Programming" manual in Microsoft Access version 1.x or the "Building Applications" manual in Microsoft Access version 2.0

MORE INFORMATION

The following example creates a procedure called RoundToNearest, which accepts three parameters:

   Parameter     Value
   ---------     ---------------------------------------------------------
   Amt           The numeric value you want to round
   RoundAmt      The increment to which Amt will be rounded
   Direction     Constant indicating which direction to round (up or down)

For example, RoundToNearest(3.33, 0.1, vb_roundup) returns the value 3.4.

1. Create a module and type the following lines in the Declarations

   section:

      Option Explicit
      Public Const vb_roundup = 1
      Public Const vb_rounddown = 0

   NOTE: In versions 1.x and 2.0, use the word "Global" instead of
   "Public."

2. Create the following procedure.

   NOTE: In the following sample code, an underscore (_) at the end of a
   line is used as a line-continuation character. Remove the underscore
   from the end of the line when re-creating this code in Access Basic.

      Function RoundToNearest (Amt As Double, RoundAmt As Variant, _
                               Direction As Integer) As Double
         On Error Resume Next
         Dim Temp As Double
         Temp = Amt / RoundAmt
         If Int(Temp) = Temp Then
            RoundToNearest = Amt
         Else
            If Direction = vb_rounddown Then
               Temp = Int(Temp)
            Else
               Temp = Int(Temp) + 1
            End If
            RoundToNearest = Temp * RoundAmt
         End If
      End Function

3. To test this function, type each of the following lines in the Debug

   window (or Immediate window in 1.x and 2.0), and then press ENTER.

      ?RoundToNearest(1.36, 0.25, vb_roundup)

   Note that the procedure returns 1.5.

      ?RoundToNearest(1.36, 0.05, vb_rounddown)

   Note that the procedure returns 1.35.

      ?RoundToNearest(1.36, 0.75, vb_roundup)

   Note that the procedure returns 1.5, which is two increments of 0.75.

NOTE: To use the above function in the ControlSource property of a control on a form, you will need to replace the constants vb_roundup and vb_rounddown with their integer values.

REFERENCES

For more information about rounding, please see the following articles in the Microsoft Knowledge Base:

   ARTICLE-ID: Q97524
   TITLE     : ACC: Round or Truncate Values to Desired Number of Decimals

   ARTICLE-ID: Q111781
   TITLE     : ACC: Rounding Errors Using Floating-Point Numbers

Additional query words: factor cents dollars quarter dime nickel

Keywords          : kbprg
Version           : 1.0 1.1 2.0 7.0 97
Platform          : WINDOWS
Hardware          : x86
Issue type        : kbhowto

Last Reviewed: November 20, 1998