How to strengthen your iPhone lock screen

Why this matters

A stolen iPhone is most attackers’ realistic target — for the resale value, the data inside, or both. Your lock-screen passcode is the only thing standing between a thief and full access to your photos, messages, banking apps, and saved passwords.

A 4-digit PIN has only 10,000 combinations and can be guessed surprisingly quickly through targeted attacks. A 6-digit numeric passcode pushes that to a million, an alphanumeric passcode pushes it to billions. Combined with Erase Data after 10 failed attempts, a stolen iPhone becomes a paperweight to anyone but you.

How to do it

1. Open Settings → Face ID & Passcode (or Touch ID & Passcode on older iPhones). Enter your current passcode.
2. Tap Change Passcode → Passcode Options. Choose 6-Digit Numeric at minimum. If you can remember it, Custom Alphanumeric is even stronger.
3. Scroll down. Turn on Erase Data. (After 10 failed passcode attempts, your iPhone wipes itself. Your iCloud backup is unaffected.)
4. Confirm Require Passcode: Immediately is set (don’t allow a grace period).
5. Turn on Stolen Device Protection at the top of the same page — this adds a 1-hour delay before sensitive changes (like turning off Find My) can be made if your iPhone is in an unfamiliar location.

What you don’t need

You don’t need a 20-character alphanumeric password — a strong 6-digit numeric passcode plus auto-erase is sufficient for most realistic threats. You also don’t need to disable Face ID or Touch ID for “security reasons” — biometrics are convenient and don’t lower your security as long as a strong passcode backs them up.