How secure is Face ID?

To use Face ID, you must set up iPhone X so that a passcode is required to unlock it. When Face ID detects and matches your face, iPhone X unlocks without asking for the device passcode.

You can always use your passcode instead of Face ID, and it’s still required under the following circumstances:

• The device has just been turned on or restarted.
• The device hasn’t been unlocked for more than 48 hours.
• The passcode hasn’t been used to unlock the device in the last 156 hours (six and a half days) and Face ID has not unlocked the device in the last 4 hours.
• The device has received a remote lock command.
• After five unsuccessful attempts to match a face.
• After initiating power off/Emergency SOS by pressing and holding either volume button and the side button simultaneously for 2 seconds.

The probability that a random person in the population could look at your iPhone X and unlock it using Face ID is approximately 1 in 1,000,000 (versus 1 in 50,000 for Touch ID). For additional protection, Face ID allows only five unsuccessful match attempts before a passcode is required to obtain access to your iPhone.

The probability of a false match is different for twins and siblings that look like you as well as among children under the age of 13, because their distinct facial features may not have fully developed. If you're concerned about this, we recommend using a passcode to authenticate.