19 ‘USSD’ Codes That Unlock Hidden Features in Your iPhone

When you want to tweak your iPhone’s preferences, you’ll usually open up the Settings app. That’s basic iOS 101. What you might not know is that there is actually another way to interact and change your device’s settings.

They’re called USSD codes, and they’re a communication protocol used by cellular telephones. But, in practical usage, they’re a way to tweak certain hidden settings and access secret features of your phone.

What Are They?

USSD codes harken back to a time before smartphones and touchscreen. Think your old, brick-like Nokia. As such, they’re entered via the Phone app in the same process as dialing a phone number.

Once the code is inputted, you can access, change or view the preferences of certain features or settings. Beyond just generally being a cool thing to know, they can even be useful.

Of course, you’ll want to be careful with some of these codes. Randomly entering some of these codes can negatively impact important settings that are pretty critical for your device. As a good rule, try not to go disabling things unless you know exactly what it is you're turning off or on.

How Do They Work?

• The process of using USSD codes is pretty simple. Just open your Phone app, tap Keypad, and enter the code.
• For the majority of these, you'll also need to hit Call (the green phone icon) to activate the code. The exceptions are noted.
• Note: Some carriers have their own specific USSD codes. Every code will not always work for every carrier.

Use the Right Arrow to Browse 19 USSD Codes That Unlock Hidden Features in Your iPhone.

19 Enter Field Mode

This will put your iPhone into Field Mode. This lets you see certain technical specifications and details about your device, and can convert the iOS signal strength indicator into an actual number. *3001#12345#*

18  See Your Unique IMEI

This displays your iPhone’s IMEI. This is a unique number used to identify your specific smartphone. Just type it in, there’s no need to hit “Call” with this code. *#06#

17  See Your Data Usage

This lets you see the current data usage on your cellular plan, as well as the remaining available data. A handy way of seeing how much data you're using before you get one of those ominous "your data is running out" texts from your ISP. *3282#

(Note: This differs slightly between carriers. See below)

• AT&T: *3282#
• Verizon: #3282
• T-Mobile: #932#

16 Call Anonymously

Dial this in front of a phone number, and your number will be hidden for that call. #31#

Alternatively, if you simply dial this number and hit "call" without a phone number, you will turn off outgoing Caller ID entirely. To turn it back on, use *31#

15 View Your Bill Balance

This lets you view your bill balance for postpaid iPhones. In other words, iPhones on a contract plan.

(Note: This differs slightly between carriers. See below)

• AT&T: *225#
• Verizon: #225
• T-Mobile: #225#

14 See If Your Phone Number Is Hidden

This will let you know if your iPhone’s number is being hidden when making outgoing calls. *#31#

If it says disabled, your outgoing caller ID is on. If it says enabled, then your number will be invisible when making calls.

13 Check Call Forwarding Settings

This lets you view your various settings for call forwarding. If you have call forwarding set up, a call to your iPhone will be forwarded to another destination:*#21#

(Note: This is simply a quick way to check your settings, you have to change them via Settings > Phone > Call Forwarding.)

12 Check Call Forwarding Number

Checks to see which number is being used for call forwarding on your iPhone when your line is currently busy. *#67#

11 Improve iPhone Call Quality

This enables Enhanced Full Rate. It’ll improve your iPhone’s call quality, but at the cost of reduced battery life: *3370

To turn it off, you'll use #3370#

(Note: this code's functionality seems to vary by carrier, device or iOS version. If you have a newer device or are using a newer version of iOS, it might not work.)

10 Check Prepaid Balance

This lets you check your account balance for iPhones on prepaid plans. *777#

9 Check Barred Features

Check to see if any kind of feature is barred for your cellular device. An example might be international calling, data calling, etc. *#33#

8 Check Available Minutes

This lets you check your remaining available minutes on your postpaid cellular plan.

(Note: This differs slightly between carriers. See below)

• AT&T: *646#
• Verizon: #646
• T-Mobile: #646#

7 Check Directed Phone Call Status

This lets you check where a phone call will be directed if you currently unreachable and call forwarding is currently disabled. *#62#

(Note: unreachable differs from busy, in #12 on this list, in that it simply means all the times when you don't answer your phone).

6 Disable Call Forwarding

Tapping this and hitting call will let you disable all call forwarding settings that you currently have set up. ##002#

5 Check Call Waiting Status

This checks your call waiting status. It’s such an integral part of modern cellular devices that you might not know what it is. Basically, call waiting is what lets you put a telephone call on “hold” to accept a second incoming call. *#43#

4 Enable Call Waiting

This enables call waiting (see previous slide). But it should already be on by default. *43#

3 Disable Call Waiting

This disables call waiting. #43#

2 Check Your Calling Line Presentation

This lets you check whether “calling line presentation” is enabled or disabled. Basically, whether an incoming call will be tagged with the caller’s state and city (if you’re in the U.S.). *#76#

(Note: Whether this works seems to differ between carriers. If it's not working for you, try *#30#)

1 See Your SMSC

This lets you check the number for your SMS Center (SMSC). Basically, it’s a network element that all text messages are sent to before being forwarded to their destination. Maybe not the most useful, but an interesting bit of trivia. *#5005*7672#