I have created a Sales Inventory Spreadsheet to help me as I put projects together that has entry fields for part number, vendor, descripiton, quantity, cost and sale price. In addition I have three columns with formulas for Extended Cost, Extended Sale and Profit Margin. This all works fine. I then modified the "sale price" to allow me to enter a number into a "Desired Margin" (DM) field and if something is entered in that field, the sale price is calculated.

=IF(DM0,(E4/(1-DM)), )

The ??

is there a way to protect the "Sell Price" field if a value is entered in DM and remove protection if the DM field is cleared?

Les