Including Formulas in a UserForm

Hi all.
Another problem. In my worksheet I have a total of 5 sheets. 1 of my sheets has a formula for calculating number of days off taken from a start date and end date, as follows.

Start Date

=DATE(YEAR(TODAY()),1,9 )

End Date

=DATE(YEAR(TODAY()),2,12 )

Number of days off

=NETWORKDAYS(Employee_Leave_Tracker!$B4,Employee_Leave_Tracker!$C4,lstHolidays)

So, when using my UserForm to input these days, it is not including the formula, so simply enters the data literally as a date.

Here is my VB code for the UserForm.

Private Sub CommandButton1_Click()
CommandButton1.Show
End Sub
Private Sub UserForm_Initialize()
'Empty StartDateBox
StartDateBox.Value = ""

'Empty EndDateBox
EndDateBox.Value = ""

'Empty selectemployeeBox
selectemployeeBox.Clear

'Fill selectemployeeBox
With selectemployeeBox
Dim rngselectemployeeBox As Range
Dim ws As Worksheet
Set ws = Worksheets("List_of_Employees")
For Each rngselectemployeeBox In ws.Range("lstEmployees")
Me.selectemployeeBox.AddItem rngselectemployeeBox.Value
Next rngselectemployeeBox
End With

'Empty LeaveTypeBox
LeaveTypeBox.Clear

'Fill LeaveTypeBox
With LeaveTypeBox
Dim rngLeaveTypeBox As Range
Set ws = Worksheets("Leave_Types")
For Each rngLeaveTypeBox In ws.Range("lstHolidayTypes")
Me.LeaveTypeBox.AddItem rngLeaveTypeBox.Value
Next rngLeaveTypeBox
End With

'Set Focus on selectemployeeBox
selectemployeeBox.SetFocus

End Sub
Private Sub SaveEntryBox_Click()
    Dim i As Integer

    'position cursor in the correct cell A4.
    Range("A4").Select
    i = 1 'set as the first ID

    'validate first three controls have been entered...
    If Me.selectemployeeBox.Text = Empty Then 'name
        Me.selectemployeeBox.SetFocus 'position cursor to try again
        Exit Sub 'terminate here - why continue?
    End If

    If Me.StartDateBox.Text = Empty Then 'StartDate
        Me.StartDateBox.SetFocus 'position cursor to try again
        Exit Sub 'terminate here - why continue?
    End If

    If Me.EndDateBox.Text = Empty Then 'EndDate
        Me.EndDateBox.SetFocus 'position cursor to try again
        Exit Sub 'terminate here - why continue?
    End If
    
    If Me.LeaveTypeBox.Text = Empty Then 'LeaveType
        Me.LeaveTypeBox.SetFocus 'position cursor to try again
        Exit Sub 'terminate here - why continue?
    End If

    'if all the above are false (OK) then carry on.
    'check to see the next available blank row start at cell A2...
    Do Until ActiveCell.Value = Empty
        ActiveCell.Offset(1, 0).Select 'move down 1 row
        i = i + 1 'keep a count of the ID for later use
    Loop

    'Populate the new data values into the 'Data' worksheet.
    ActiveCell.Value = i 'Next ID number
    ActiveCell.Offset(0, 0).Value = Me.selectemployeeBox.Text 'set col A
    ActiveCell.Offset(0, 1).Value = Me.StartDateBox.Text 'set col B
    ActiveCell.Offset(0, 2).Value = Me.EndDateBox.Text 'set col C
    ActiveCell.Offset(0, 3).Value = Me.LeaveTypeBox.Text 'set col D

    'Clear down the values ready for the next record entry...
    Me.selectemployeeBox.Text = Empty
    Me.StartDateBox.Text = Empty
    Me.EndDateBox.Text = Empty
    Me.LeaveTypeBox.Value = Empty

    Me.StartDateBox.SetFocus 'positions the cursor for next record entry

End Sub
Private Sub ClearBox_Click()
Call UserForm_Initialize
End Sub
Private Sub CancelBox_Click()
    'close the form (itself)
    Unload Me
End Sub

How can I include the formulas using my UserForm ?
And Im still learning Excel and VB