Many individuals and businesses use Excel spreadsheets to calculate and monitor sensitive financial information. Microsoft Excel contains many features to protect the data in a worksheet. Password protecting a spreadsheet requires a password to open and modify a spreadsheet. To password protect your Excel file you must encrypt the spreadsheet. Encrypting a spreadsheet converts the text of the document to an unreadable format. Upon entering the password, Microsoft Excel converts the document to its original format, allowing the user to view the information in the spreadsheet.
Open the Excel file that you intend to password protect.
Click the "File" tab and click "Info."
Click "Protect Workbook" and then click "Encrypt with Password."
Enter a password and click "OK." The password is active immediately.
If you lose the spreadsheet password, Microsoft cannot help you retrieve it. Keep the password in a safe place.