Truncating Double with VBA in excel - 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?

Answer 1

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".

Answer 2

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

Answer 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

Answer 4

This was my attempt:
Function TruncateNumber(decimalNum As Double, decPlaces As Integer) As Double
'decimalNum: the input number to be truncated
'decPlaces: how many decimal places to round to. Use 0 for no decimal places.
decimalLocation = InStr(decimalNum, ".")
TruncateNumber = Left(decimalNum, decimalLocation + decPlaces)
End Function
It uses strings to avoid any math errors caused by different rounding methods. It will output as a type double, so you can still perform your own math on it.
This will cause an error if a number without a decimal place is passed into the above function. If this is a concern, you can use the following code instead:
Function TruncateNumber(decimalNum As Double, decPlaces As Integer) As Double
'decimalNum: the input number to be truncated
'decPlaces: how many decimal places to round to. Use 0 for no decimal places.
If InStr(decimalNum, ".") = 0 Then 'if there was no decimal:
'then return the number that was given
TruncateNumber = decimalNum
Else 'if there is a decimal:
'then return the truncated value as a type double
decimalLocation = InStr(decimalNum, ".")
TruncateNumber = Left(decimalNum, decimalLocation + decPlaces)
End If
End Function
Hopefully these functions are of some use to someone. I haven't done extensive testing, but they worked for me.

Answer 5

EDITED
Newer version of Excel (VBA) have a TRUNC function which already does things properly.
For older versions of EXCEL
I wanted to truncate a double into an integer.
value = Int(83.768)
value == 83
Awesome, it worked.
Depending on your version of Excel (VB) this might not work with negative numbers.
value = Int(-83.768)
value == -84
VB uses Banker rounding.
Public Function Trunc1(ByVal value As Double) As Integer
' Truncate by calling Int on the Absolute value then multiply by the sign of the value.
' Int cannot truncate doubles that are negative
Trunc1 = Sgn(value) * Int(Abs(value))
End Function
If you want specific decimal places do what Makah did only with Abs around the value so Int can truncate properly.
Public Function Trunc2(ByVal value As Double, Optional ByVal num As Integer = 1) As Double
' Truncate by calling Int on the Absolute value then multiply by the sign of the value.
' Int cannot truncate doubles that are negative
Trunc2 = Sgn(value) * (Int(Abs(value) * (10 ^ num)) / (10 ^ num))
End Function

Answer 6

Here is a little experiment I did... (1st time posting and answer, please tell me if I am not following conventions.
Sub Truncate()
Dim dblNum As Double
Dim intDecimal As Integer
dblNum = 1578.56789
intDecimal = 2 '0 returns 1578
'2 returns 1578.56
'-2 returns 1500
Debug.Print (Int(dblNum * 10 ^ intDecimal) / 10 ^ intDecimal)
End Sub