Best way to make multiple countdown timers

Hi Dave_ross
Try this code in you workbook

Option Explicit
Dim iTimer As Date
Dim zTimer As Date
Dim xCount As Date
Dim iCount As Date
Dim eTime As Date
  Dim XCell As Range
Dim iBoolean As Boolean
Dim iiBoolean As Boolean
Dim iiiBoolean As Boolean
Sub start_timers()
    With ThisWorkbook.Sheets(1)
        .Range("C3") = TimeValue("00:00:10")
        .Range("E3") = TimeValue("00:00:10")
        .Range("G3") = TimeValue("00:01:50")
        .Range("G10") = ""
        .Range("C10") = "Started"
    End With
  iBoolean = True
iiBoolean = True
iiiBoolean = True
    MasterTimer
End Sub
Sub MasterTimer()
  
    
    If iBoolean Then
        xCount = TimeValue("00:00:10")
        Set XCell = ThisWorkbook.Sheets(1).Range("C3")
        eTime = TimeValue("00:00:10")
        iCount = TimeValue("00:00:01")
        iBoolean = False
        UpdateiTimer
        STimer
    ElseIf iiBoolean Then
        xCount = TimeValue("00:00:10")
        iCount = TimeValue("00:00:01")
        Set XCell = ThisWorkbook.Sheets(1).Range("E3")
        eTime = TimeValue("00:00:10")
         iiBoolean = False
        UpdateiTimer
        STimer
    ElseIf iiiBoolean Then
        xCount = TimeValue("00:01:50")
        iCount = TimeValue("00:00:01")
        Set XCell = ThisWorkbook.Sheets(1).Range("G3")
        eTime = TimeValue("00:01:50")
         iiiBoolean = False
        UpdateiTimer
        STimer
    Else
        KillTimers
    End If
End Sub
Sub UpdateiTimer()
    XCell = xCount
    iTimer = Now + TimeValue("00:00:01")
    xCount = xCount - iCount
    Application.OnTime iTimer, "UpdateiTimer"
End Sub
Sub STimer()
    zTimer = Now + eTime
    Application.OnTime zTimer, "StopTimers"
End Sub
Sub StopTimers()
    On Error Resume Next
    Application.OnTime iTimer, "UpdateiTimer", , False
    Application.OnTime zTimer, "STimer", , False
    MasterTimer
End Sub
Sub KillTimers()
    On Error Resume Next
    Set XCell = Nothing
     Application.OnTime iTimer, "UpdateiTimer", , False
    Application.OnTime zTimer, "STimer", , False
    ThisWorkbook.Sheets(1).Range("G10") = "Stopped"
    ThisWorkbook.Sheets(1).Range("C10") = ""
End Sub

but dont forget to put

Private Sub Workbook_BeforeClose(Cancel As Boolean)
 Call KillTimers
End Sub

in "Thisworkbook" Module