Dim t As Double
Dim elapsed As Double

t = Timer

' --- 計測したい処理 ---
Call YourLogic

elapsed = Timer - t
If elapsed < 0 Then
    elapsed = elapsed + 86400   ' 24時間 = 86400秒
End If

Debug.Print "処理時間: " & Format(elapsed, "0.000") & " 秒"