How to lock cells and protect a sheet in Excel

The short answer

Locking cells in Excel is a two-step job, and the order is the part everyone misses.

1. Every cell is already locked by default. The setting has no effect on its own.
2. Select the cells you want people to be able to type in and untick Locked in Format Cells.
3. Go to Review > Protect Sheet and click OK. Now the locked cells are read-only and your input cells still work.

If you skip step 3, nothing changes. If you skip step 2, the whole sheet becomes read-only, including the cells you meant to leave open.

The steps in full

1. Press Ctrl+A to select the whole sheet, press Ctrl+1 for Format Cells, go to the Protection tab and confirm Locked is ticked. This is the default, so it usually already is.
2. Now select only the cells people should fill in. Hold Ctrl to pick several ranges at once.
3. Ctrl+1 again, Protection tab, untick Locked, OK.
4. Review > Protect Sheet. In the dialog, leave the default selection options ticked and choose whatever else you want to allow (sorting, filtering, formatting).
5. Set a password only if you need one, then click OK.

Once protected, pressing Tab moves between the open cells only, which makes a form quick to fill in. That is a nice side effect worth designing for.

Protection is for preventing accidents, not for keeping secrets. Treat it as a guard rail, not a lock on a door.

Hiding formulas

The same dialog has a Hidden tickbox. Tick it on your formula cells before protecting, and the formulas stop appearing in the formula bar. The results still show. It is useful when a sheet goes to people who might helpfully "fix" your calculations.

Protect the workbook, not just the sheet

Two different commands:

• Protect Sheet controls what can be edited on one tab.
• Protect Workbook (also on the Review tab) stops people adding, deleting, renaming, hiding or reordering tabs.

Use both on a template that gets sent out, or someone will delete the Lists tab your drop downs point at and email you when it breaks.

What this does not do

Be clear with yourself about the limits. Sheet protection is not encryption. It stops a colleague from accidentally overwriting a formula, and that is genuinely valuable, but it is not a security control for confidential data. Microsoft's Excel help is explicit about the difference, and Microsoft Learn covers the stronger options.

If a file genuinely holds sensitive information, control who can open it: file permissions, a shared drive with proper access, or file-level encryption. Do not lean on a sheet password.

A design that survives contact with colleagues

Protection works best alongside a bit of layout discipline:

• Put inputs in one obvious block, shaded a different color, and untick Locked on only those.
• Put the calculation sheet on its own tab and hide it, then protect the workbook so it stays hidden.
• Add drop down lists on the input cells so people pick rather than type.
• Write one line at the top saying what the sheet is for. Future you will be grateful.

A protected sheet with no instructions still generates emails. A protected sheet with a clear input block generates almost none.

When you need more than this

If you find yourself protecting a workbook that four people edit at once, you have outgrown the spreadsheet and want a proper tool with permissions. Notion or Airtable are the usual next step for shared, structured data.

If you want the full Excel skill instead, the Excel certificate covers protection alongside formulas, lookups and reporting, and one subscription opens every course in the Business & Productivity school.

Lock the formulas, open the inputs, and stop rebuilding the sheet every time someone types over a cell.