Protect a Sheet in Excel: stop accidental edits in 3 clicks

Protecting a sheet stops people changing cells. Used well, it keeps formulas safe while inputs stay open.

Protect everything (3 clicks)

1. Review › Protect Sheet.
2. Type a password (optional). OK. Confirm.

Every cell is now read-only.

Leave some cells editable (the usual case)

1. Before protecting: select the input cells. Ctrl + 1 › Protection › untick Locked. OK.
2. Now Review › Protect Sheet.

Those cells accept typing; everything else refuses. Detailed walk-through: lock cells.

What users may still do

In the Protect Sheet dialog, tick what to allow: Format cells, Sort, Use AutoFilter, Insert rows. Untick Select locked cells if you want Tab to jump between inputs only.

Unprotect

Review › Unprotect Sheet › password.

Check it worked

Click a formula cell and type — Excel refuses. Click an input cell — it works.

What it does not do

Sheet protection is not security. Anyone can copy the sheet to a new workbook or open it in Google Sheets. To stop the file being opened at all, use a file password.

Common mistake

Forgetting to unlock the input cells first — then nobody can enter anything, including you. Unprotect, unlock inputs, protect again.