What does pressing *#21 do on iPhone?

What Happens When You Dial *#21# on Your iPhone?

Ever wondered what those mysterious codes do when you type them into your iPhone? One of the most talked-about sequences is *#21#. Contrary to some myths, this isn’t a magic hack or a spy tool—it’s actually a built-in feature tied to call forwarding settings.

When you dial *#21# and press call, your phone checks the status of call forwarding. This means it reveals whether your incoming calls are being redirected to another number—something you might have set up yourself for convenience, like sending calls to voicemail when busy. But more importantly, it can help you spot unauthorized activity.

If the screen shows “Call Forwarding: Off,” you’re good—no one’s rerouting your calls. But if it says “On” and you didn’t enable it, that could be a red flag. While it doesn’t confirm someone is spying on you, unexpected call forwarding could mean someone had access to your device and set it up without your knowledge.

It’s worth noting that this code works on most GSM networks and isn’t exclusive to iPhones. However, newer iOS versions may display the result in a more user-friendly way or simply show a blank screen if forwarding is disabled.

So, should you be worried? Probably not—most cases of accidental or unauthorized forwarding are rare. But if you’re concerned about privacy, checking *#21# every now and then is a quick, easy way to stay in control. Just remember: knowledge is power, especially when it comes to your phone’s security.