How to Lock Your Phone with a Strong Passcode

Choose a better code

• Use at least six non-obvious digits, or a longer alphanumeric passcode where practical.
• Avoid birthdays, addresses, repeated digits and simple patterns.
• Do not reuse a banking PIN or voicemail PIN.
• Do not store the code in an unlocked note on the same phone.

Reduce shoulder-surfing risk

Shield the screen when entering the code in public. Prefer biometrics for routine unlocking, but remember that Face ID or fingerprint unlock does not replace the passcode.

Set sensible locking behaviour

• Use a short automatic-lock delay.
• Require authentication for purchases and password access.
• Hide one-time codes and private message previews on the lock screen.
• Enable theft-protection features supported by the device.

If someone may know the code

1. Change it immediately in a safe place.
2. Review Apple/Google account security.
3. Check payment cards, password managers and saved sessions.
4. Consider whether any biometric enrolment or recovery setting was changed.

Recovery without weakening security

A forgotten passcode can require erasing the device, so maintain a verified backup and account recovery route. Do not weaken the code merely because no backup exists; fix the backup problem first.

Test security without creating a lockout

A stronger code should remain memorable to the owner and should not be stored in an obvious note on the same phone.

• Use a longer numeric or alphanumeric code instead of a short repeating pattern.
• Confirm account-recovery details before changing it.
• Check that emergency information remains available without exposing messages or one-time codes.