How to Password Protect an Excel File: Complete Guide for Every Platform

Spreadsheets hold some of the most sensitive information in any organization. Payroll figures, client contact lists, quarterly forecasts, tax calculations, HR records. If any of these fall into the wrong hands, the consequences can be severe.

The good news: Microsoft Excel has built-in encryption that uses AES-256, the same standard banks and governments rely on. The bad news: most people either skip it entirely or have no idea how to share the password safely afterward.

This guide walks you through every method, platform by platform, and then tackles the part everyone forgets: getting the password to the right person without exposing it.

Why You Should Password Protect Excel Files

Before diving into the steps, consider what is typically stored in spreadsheets:

• Financial data: budgets, invoices, revenue projections
• HR records: salaries, social security numbers, performance reviews
• Client lists: contact details, contract terms, pricing
• Personal information: tax returns, medical expenses, loan applications

An unprotected Excel file attached to an email is essentially a postcard. Anyone who intercepts it, or anyone with access to the recipient's inbox, can open it instantly.

Method 1: Excel on Windows (Desktop)

This is the most robust option. Excel for Windows supports AES-256 encryption, which is virtually unbreakable with a strong password.

Steps:

1. Open your Excel file
2. Click File in the top menu
3. Select Info
4. Click Protect Workbook
5. Choose Encrypt with Password
6. Enter a strong password and click OK
7. Re-enter the password to confirm
8. Save the file

From this point on, anyone who opens the file will be prompted for the password. Without it, the contents are completely inaccessible.

Tips for a strong password:

Weak	Strong
company2026	Tr!8kQ#mP2x&vL
password123	9Fj$wKn!4Rb@eZ
budget	mY_Budg3t!F1le#2026

Use at least 12 characters with a mix of uppercase, lowercase, numbers, and symbols.

Method 2: Excel on Mac

The process on Mac is slightly different from Windows.

Steps:

1. Open your Excel file
2. Click Review in the top menu
3. Click Protect Workbook (or go to File > Passwords)
4. Enter a password under Password to open
5. Optionally enter a separate Password to modify
6. Click OK and confirm
7. Save the file

Mac versions of Excel also support AES-256 encryption, so the protection level is identical to Windows.

Method 3: Google Sheets (Workaround)

Here is the unfortunate truth: Google Sheets does not support password protection. There is no way to set a password on a Google Sheets file.

What you can do instead:

• Restrict sharing: Click Share and limit access to specific email addresses
• Set view-only permissions: Prevent editing by choosing "Viewer" access
• Disable downloading: In sharing settings, uncheck "Viewers and commenters can download, print, and copy"
• Use link expiration: Share via Google Workspace features with time-limited access

These are access controls, not encryption. Google can still read the file, and anyone with access can take screenshots. If you need true password protection, download the file as .xlsx and encrypt it using Excel or LibreOffice.

Method 4: LibreOffice Calc

LibreOffice is a free, open-source alternative that also supports file encryption.

Steps:

1. Open or create your spreadsheet in LibreOffice Calc
2. Click File > Save As
3. Check the box labeled Encrypt with GPG Key or Save with Password
4. Enter a password and confirm
5. Click Save

LibreOffice uses AES-256 encryption when saving in .xlsx format, making it fully compatible with Microsoft Excel. If you save in .ods format, it uses Blowfish encryption by default.

Excel Online: The Limitation You Need to Know

Excel Online (the browser version) cannot encrypt files. You can open and edit password-protected files if you know the password, but you cannot set or change a password through the web interface.

If you need to add encryption, you must:

1. Download the file
2. Open it in the desktop version of Excel or LibreOffice
3. Apply the password
4. Re-upload the file

This is an important consideration for teams that rely solely on Microsoft 365 in the browser.

Understanding the Three Types of Excel Protection

Excel offers different levels of protection. They are not the same thing.

Protection Type	What It Does	Security Level
Open Password	Encrypts the entire file with AES-256	Very High
Modify Password	Allows viewing but blocks editing without password	Low
Sheet Protection	Prevents changes to specific cells or sheets	Very Low

Important: Sheet protection and modify passwords are not encryption. They can be bypassed with freely available tools in seconds. Only the open password provides real security through AES-256 encryption.

If you need to prevent unauthorized access to the data itself, always use the open password (Encrypt with Password).

The Forgotten Step: How to Share the Password Safely

You have encrypted your file. Now you need to send it to a colleague, client, or accountant. This is where most people make a critical mistake.

What NOT to do:

• Send the file and the password in the same email
• Put the password in the email subject line
• Text the password through iMessage or Messenger in the same thread where you shared the file
• Write the password in a shared document

If someone gains access to your email, they get both the file and the password. The encryption becomes meaningless.

A better approach:

Send the file and the password through different channels. For example, email the file and share the password through a separate, secure method.

LOCK.PUB lets you create a password-protected, self-expiring link that contains your Excel file password. You set it up in seconds:

1. Go to lock.pub and create a secret memo
2. Type the Excel password into the memo
3. Set an expiration (e.g., 24 hours or after first view)
4. Share the LOCK.PUB link with your recipient

The recipient opens the link, enters the access code, sees the password, and the memo expires automatically. No trace left in email, no screenshot-friendly chat bubble, no permanent record.

Quick Reference: Platform Comparison

Feature	Excel Windows	Excel Mac	Google Sheets	LibreOffice	Excel Online
AES-256 Encryption	Yes	Yes	No	Yes (.xlsx)	No
Open Password	Yes	Yes	No	Yes	No
Modify Password	Yes	Yes	No	Yes	No
Sheet Protection	Yes	Yes	Yes	Yes	Yes
Free	No	No	Yes	Yes	Yes

Final Thoughts

Password protecting an Excel file takes less than a minute. The encryption behind it, AES-256, is military grade. But encryption is only as strong as your password delivery method.

Encrypt the file. Use a strong password. And share that password through a secure, temporary channel like LOCK.PUB so it does not end up sitting in someone's inbox forever.

Your spreadsheet data deserves the same level of care you put into creating it.