In Excel: go to File ▸ Info ▸ Protect Workbook ▸ Encrypt with Password, set a password, and the whole .xlsx then requires it to open.
Open File ▸ Info, click Protect Workbook, and choose Encrypt with Password.
Type a strong password, click OK, then re-enter it to confirm.
Save the file (Ctrl+S) so the encryption is written to disk.
Test it by closing and reopening the workbook — it should prompt for the password before opening.
What this does
Encrypting a workbook with a password locks the entire file so it cannot even be opened without the password — the contents are scrambled on disk, not merely set to read-only. This is workbook-level (file-level) encryption, reached through File ▸ Info ▸ Protect Workbook ▸ Encrypt with Password, and it is completely separate from sheet protection: it controls who can open the file at all, rather than which cells can be edited once it is open. Keep the inputs visible and clearly labelled and the whole thing stays auditable — anyone who opens the file later, including you, can see at a glance exactly what feeds the result and change one assumption without hunting through the formula. Treat “make an excel sheet password protected” as a small repeatable workflow rather than a one-off click you hope to remember next time. Use a small test block before the live file, so any surprise in the affected sheet shows up while it is still harmless. When this is a ribbon command, the selection matters more than the button: confirm the range, apply the command, then spot-check the output before saving. That turns a workspace setting that makes a big sheet comfortable to navigate into a method you can reuse, explain, and defend when the workbook leaves your screen.
A worked example
You have a payroll workbook to email. Open File ▸ Info ▸ Protect Workbook ▸ Encrypt with Password, type a password such as Spr1ng!2026, confirm it, and save. The next time anyone — including you — double-clicks the .xlsx, Excel demands that password before it will display a single cell. Without it the file is unreadable; lose the password and there is no built-in way back in. Encrypt a workbook when the whole document is sensitive — salaries, contracts, personal data — and must not be readable by anyone who gets the file. It is the right tool when the goal is "nobody opens this without the password", as opposed to merely keeping a few formula cells from being overwritten. A practical tip before you scale it up: build it once on a small block of test data, confirm the number against the tool on this page, and only then point it at your real sheet. That one habit catches almost every mistake while it is still cheap to fix, long before a wrong figure reaches a report or a colleague.
In Google Sheets
Everything above works in Google Sheets too. Excel and Sheets share the formula syntax used here; only the surrounding menus are arranged differently. That portability is deliberate — learn it once and it follows you between the two tools and across Windows and Mac. The aim was to get you unstuck fast and leave you a little more capable than a copy-paste would. The answer is at the top, the tool proves it, and the detail above shows why it holds — so the next time a colleague asks, you can answer without reaching for search. The short version of “make an excel sheet password protected”: the answer is at the top of this page, the tool proves it on your own numbers, and the sections above explain why it holds so the next variation does not stump you. Excel rewards people who reference cells instead of typing values and who keep inputs separate from formulas, because that is what makes a result you can audit months later. Build it once, deliberately, with the live tool as a check, and you convert a one-off lookup into a reusable skill — which is the whole point of learning the why and not just the what.
Common mistakes
- Confusing this with Protect Sheet — encryption controls opening the file, not which cells can be edited.
- Losing the password: encrypted workbooks have no official recovery, so a forgotten password can mean permanent lockout.
- Assuming a read-only or "mark as final" setting is encryption — only Encrypt with Password actually scrambles the file.
- Relying on it for a shared OneDrive file where co-authoring expects an unencrypted document; encryption can block online editing.
Frequently asked questions
Is encrypting the file the same as protecting a sheet?
No. Encryption stops the file from opening without a password; sheet protection (Review ▸ Protect Sheet) lets the file open but locks certain cells from editing.
Can I remove the password later?
Yes — open the file with the password, return to File ▸ Info ▸ Protect Workbook ▸ Encrypt with Password, clear the password box, and save.
What if I forget the password?
There is no official Microsoft bypass for a forgotten open-password; the encryption is genuine, so always store it somewhere safe before you rely on it.
Other ways people ask this
People reach this page typing “how to make excel sheet password protected” and “how to make password protected excel sheet”, among other phrasings; whichever wording you used, the fix above is the one you want.
Why do people search for this in so many different ways?
Because the same task has many names. “how to make excel sheet password protected”, “how to make password protected excel sheet” all point at the one operation explained on this page, which is why they all lead here.