Password Protect an Excel File
Upload an .xlsx workbook, set a password, and download a natively encrypted Excel file. Unlike ZIP-based tools, this applies real Office AES encryption — the same encryption Excel itself uses when you go to File → Info → Protect Workbook → Encrypt with Password.
Encrypt Excel File FreeNative AES encryption vs ZIP wrapping
Native Office encryption (this tool)
- • Applies real AES-128/AES-256 encryption inside the OOXML container
- • File stays .xlsx — opens natively in any Excel version
- • Excel recognizes it as "Encrypted Workbook" and prompts for password
- • Compatible with Excel 2007 through Microsoft 365
ZIP wrapping (other tools)
- • Wraps your .xlsx inside a password-protected .zip file
- • Recipient gets a .zip, not an .xlsx — confusing and unprofessional
- • Excel can't open it directly — you must extract first
- • ZIP passwords are weaker than AES-256 (ZipCrypto is vulnerable)
Which Excel encryption version you get
The tool encrypts using the strongest AES variant compatible with your file's format:
| Your file format | Encryption applied | Opens in |
|---|---|---|
| .xlsx (Office 2007+) | AES-256, SHA-512, 100,000 iterations | Excel 2007 through Microsoft 365 |
| .xls (Office 97-2003) | Not supported — use "Save As .xlsx" first, then encrypt | Convert to .xlsx for strong encryption |
Why .xls files aren't supported: The legacy .xls format uses 40-bit RC4 encryption — that's the weak encryption we can break on the recovery side. If you want real protection, save as .xlsx first (File → Save As → Excel Workbook), then encrypt the .xlsx. The 40-bit RC4 in .xls is trivially recoverable by anyone with a GPU.
Password tips specific to Excel
- Don't reuse the sheet protection password. Workbook encryption and sheet protection are separate layers. Use a strong password for file-open encryption — sheet protection is trivial to bypass.
- Store the password in a password manager immediately — before you even close the dialog. If you forget an AES-256 Excel password and it's not a dictionary word, recovery is infeasible.
- Excel VBA project passwords are separate. Encrypting the workbook doesn't protect VBA code. Use the VBA editor's own protection (Tools → VBAProject Properties → Protection) for macros — but know that it's structurally removable.
For Word and PowerPoint encryption, see Free Office Encryption. If you already have a locked Excel file and need to open it, use Excel password recovery.