To reproduce: Me.RadMaskedEditBox1.Mask = "c" Me.RadMaskedEditBox1.MaskType = MaskType.Numeric Me.RadMaskedEditBox1.Value = Nothing Try to enter "123". You will notice that after entering "1", the cursor is positioned after "$" instead of "1". Thus, the entered value will be "$231.00", instead the expected "$123.00" Workaround: initialize the RadMaskedEditBox with Value= 0.