Truncating Double with VBA in excel

Question

I need to truncate the amount of decimal places of my double value for display in a textbox. How would one achieve this with vba?

Solution 1

You can either use ROUND for FORMAT in VBA

For example to show 2 decimal places

Dval = 1.56789

Debug.Print Round(dVal,2)

Debug.Print Format(dVal,"0.00")

Note: The above will give you 1.57. So if you are looking for 1.56 then you can store the Dval in a string and then do this

Dim strVal As String

dVal = 1.56789
strVal = dVal

If InStr(1, strVal, ".") Then
    Debug.Print Split(strVal, ".")(0) & "." & Left(Split(strVal, ".")(1), 2)
Else
    Debug.Print dVal
End If

Solution 2

If you want to round the value, then you can use the Round function (but be aware that VBA's Round function uses Banker's rounding, also known as round-to-even, where it will round a 5 up or down; to round using traditional rounding, use Format).

If you want to truncate the value without rounding, then there's no need to use strings as in the accepted answer - just use math:

Dim lDecimalPlaces As Long: lDecimalPlaces = 2
Dim dblValue As Double: dblValue = 2.345

Dim lScale = 10 ^ lDecimalPlaces
Dim dblTruncated As Double: dblTruncated = Fix(dblValue * lScale) / lScale

This yields "2.34".

Solution 3

You can use Int() function. Debug.print Int(1.99543)

Or Better:

Public Function Trunc(ByVal value As Double, ByVal num As Integer) As Double
  Trunc = Int(value * (10 ^ num)) / (10 ^ num)
End Function

So you can use Trunc(1.99543, 4) ==> result: 1.9954

Comments

[GlennFromIowa]

I had forgotten about the Banker's rounding. +1 despite the condescending "just use math" jab. For just displaying the number as the OP requested, if you don't care much about rounding, Format() is the tool for the job, and is simpler than Fix() (or Int(), which is equivalent to Fix() for positive numbers). However, there are cases where Banker's rounding will cause user questions and require a more complex transformation.

[vpprof]

There is a sign function that achieves sign = Abs(value) / value in one step: Sgn(value).

[Gustav]

Never handle numbers as text.