Sub pricepercincrease()
Dim priceincrease, percentage As Variant
Dim r1, r2, wrange As Range
Dim selecttab As String
Dim promptmsgbox As Integer

On Error GoTo errorend
percentage = InputBox("Please enter the percentage you wish to increase by?", "Price Increase")
priceincrease = (percentage / 100) + 1
selecttab = InputBox("Please select a worksheet to increase?" & vbNewLine & vbNewLine & "1. Discounts C&P" & vbNewLine & "2. Finishing" & vbNewLine & "3. Air Valves & Circulars" & vbNewLine & "4. Ceiling Diffusers" & vbNewLine & "5. Ceiling Swirls" & vbNewLine & "6. Displacement Vents" & vbNewLine & "7. Fireblocks & PSG" & vbNewLine & "8. Floor Grilles" & vbNewLine & "9. Floor Diffusers & Swirls" & vbNewLine & "10. High Induction Slots" & vbNewLine & "11. Jet & Cylinder" & vbNewLine & "12. Laminar Flow Panels" & vbNewLine & "13. Linear Bar Grilles" & vbNewLine & "14. Linear Fixed Ceiling Diffuser" & vbNewLine & "15. Linear Slot Diffusers" & vbNewLine & "16. Louvres" & vbNewLine & "17. OBD" & vbNewLine & "18. Plenums" & vbNewLine & "19. Security Grilles" & vbNewLine & "20. Wall Grilles" & vbNewLine & "21. Contract Diffuser Range" & vbNewLine & "22. Fixings" & vbNewLine & "23. TEST", "Tab Increase")
Select Case selecttab
    '1. Discounts C&P
  Case 1
    promptmsgbox = MsgBox("This is will update Discounts C&P by " & percentage & "%", vbCritical + vbYesNo + vbDefaultButton2, "Continue?")
    If promptmsgbox = vbYes Then
      Set wrange = ThisWorkbook.Worksheets("Test").Range("H21, H23, H25")
      MsgBox (percentage)
      MsgBox (priceincrease)
      For Each cell In wrange
        cell.Value = WorksheetFunction.Round(cell.Value * priceincrease, 2)
        cell.NumberFormat = "0.00"
      Next cell
      wrange.Select
    End If
End Select
Exit Sub
errorend:
MsgBox ("An error has occured when trying to increase " & selectab)

End Sub