How to encrypt a file on Windows, Mac and before you send it

Start with what you're trying to protect the file from, because that decides which kind of encryption works:

The last two rows are the trap. They protect files while they're on your device, but the moment you copy a file somewhere else or attach it to an email, it's a normal, readable file again. To send something privately, you need one of the first three.

With 7-Zip (free, any edition of Windows)

7-Zip is a free, open-source app that puts files into an archive protected with AES-256 encryption. It works on every edition of Windows, and the encrypted file can be sent to anyone.

1. Install 7-Zip from 7-zip.org.
2. Right-click the file or folder and choose 7-Zip > Add to archive. On Windows 11, you may need to click Show more options first.
3. Choose 7z as the archive format, or zip if your recipient uses another archive app, like WinRAR.
4. Under Encryption, enter a password twice and pick AES-256. With the 7z format, also tick Encrypt file names, so nobody can see what's inside without the password.
5. Click OK, then delete the original if you no longer need an unencrypted copy.

Your recipient needs 7-Zip or a similar app to open it, because Windows' own zip tool doesn't support encrypted archives. For more on zip files, see our guide to sending a zip file.

With Windows' built-in file encryption (not on Home)

1. Right-click the file or folder and choose Properties.
2. Click Advanced and tick Encrypt contents to secure data.
3. Click OK, then Apply, then OK.

This isn't available in the Home edition of Windows. It also only protects the file on your PC, under your Windows account: Microsoft warns that encrypted files you put in a zip folder come out unencrypted when they're unzipped. Use it for files you keep, not files you send.

Encrypt your whole PC

Device Encryption encrypts your entire drive, so your files are safe if your laptop is stolen. It's switched on automatically when you sign in with a Microsoft account on supported PCs. You can check it in Settings > Privacy & security > Device encryption.

With an encrypted disk image

An encrypted disk image is a password-protected container for files, built into every Mac:

1. Open Disk Utility and choose File > New Image > Blank Image.
2. Give it a name, choose where to save it, and set a size big enough for your files.
3. Set Format to APFS, then click the Encryption menu, choose an encryption option, and enter a password twice.
4. Leave the other options as they are, click Save, then Done.
5. Copy your files onto the disk image that opens in Finder, then eject it.

To encrypt a folder you already have, choose File > New Image > Image from Folder instead. Remember to eject the image when you're done: as long as it's open, anyone using your Mac can see the files. Disk images are a Mac format, so this is best for files you keep, not files you send to Windows users.

Encrypt your whole Mac

FileVault encrypts everything on your Mac's startup disk, and Apple turns it on by default on Macs running macOS 26.4 or later. You'll find it in System Settings > Privacy & Security.

Word, Excel and PowerPoint

In the desktop app, go to File > Info, click Protect Document (Protect Workbook in Excel, Protect Presentation in PowerPoint) and choose Encrypt with Password. Enter the password twice, then save the file. Anyone opening it now needs the password, on any computer.

PDFs on a Mac

1. Open the PDF in Preview and choose File > Export.
2. To keep the original as it is, give the copy a new name.
3. Click Permissions, select Require Password To Open Document and enter a password.
4. Enter an owner password too, then click Apply and Save.

PDFs on Windows

Windows has no built-in way to password-protect a PDF. Put it in an encrypted 7-Zip archive as shown above, or use a PDF editor that supports passwords.

Watch out for features that sound similar but don't encrypt anything. Restrict Editing in Word and the Locked option in Preview only stop changes. Anyone can still open and read the file.

Your phone already does it. iPhones encrypt every file with its own key as it's saved, and new Android phones have used file-based encryption since Android 10. Setting a strong passcode is what keeps that encryption locked.

Like file encryption on a computer, this only protects files while they're on your phone. To send a file from your phone so only the right person can open it, use an encrypted link, as below.

Option 1: An end-to-end encrypted link

The simplest way to send a file privately is a link that's encrypted end to end. VeilShare encrypts every file with AES-256-GCM in your browser before it's uploaded. The key is in the part of the link after the #, which browsers never send to a server, so we only ever store scrambled data and can't read your files.

1. Drop your file onto the upload box on our homepage, on a computer or a phone.
2. Pick how long the link should last, 6, 24, 48 or 72 hours, and add a password if wanted.
3. Click on the upload button and send the link. If you added a password, send it another way.

Your recipient opens the link in any browser, with nothing to install, and the link stops working when it expires. It's free up to 3 GB without an account. Read more about how VeilShare encrypts files.

Option 2: An encrypted file by email

Encrypt the file with 7-Zip or Office as above, attach it and send it. Then send the password some other way, like a text message or a phone call. If the password is in the same email, anyone who gets into that inbox gets the file too. Encrypted 7-Zip files still count toward the 20 to 25 MB attachment limit, and Gmail blocks password-protected archives that contain another archive.

Sending ID or financial documents? Our guide to emailing a copy of your passport covers why plain email attachments are risky.

Real encryption has no back door. Apple warns that if you forget the password to an encrypted disk image, you won't be able to open it, and Microsoft says Word can't recover a forgotten document password. So:

• Use a long passphrase of several random words. It's easier to remember and harder to guess than a short, complicated password.
• Save it in a password manager before you encrypt anything.
• Never send a password in the same message as the file it protects.