What is *21*# used for?

What Does *#21# Do on Your Phone?

Ever wondered what those mysterious codes like *#21# actually do on your phone? Contrary to some misinformation floating around, this isn't a way to enable or disable a hack—far from it. In fact, *#21# is a simple USSD (Unstructured Supplementary Service Data) code used primarily to check if your calls, texts, or data are being forwarded to another number.

When you dial *#21#, your phone sends a request to your carrier asking: “Is call forwarding active?” The result will appear on your screen almost instantly, usually showing whether calls, SMS, or other services are being redirected, along with the destination number if applicable. It’s a transparency feature, not a security flaw.

Now, if you discover that forwarding is turned on and you didn’t set it up, that might raise a few concerns. But before jumping to conclusions, remember that call forwarding can be activated intentionally—maybe during travel, network issues, or through a previous carrier setting. If you want to disable all forwarding at once, you can use *#002#. This code resets call, text, and data forwarding settings to default, ensuring nothing is being rerouted.

It’s important to note that these codes only work on GSM networks and aren’t universal across all carriers or regions. Some phones may even display the info differently or require a menu dive through settings instead.

So, rather than a secret spy tool, *#21# is just a handy, built-in diagnostic feature. Think of it as a quick health check for your call settings—simple, useful, and completely safe.