How Are Phone Unlock Codes Generated? (Explained!)

Cell phones bought from a carrier or network provider are usually locked for the length of your contract which means you aren’t able to use it with any other carrier or network provider unless you network unlock your phone.

To network unlock your phone you need an unlocking code that is entered into the phone so the phone can be used on any carrier network.

Please note that the process of unlocking the iPhone is different from the Android phone which will be covered later in this article.

Unlock code databases based on IMEI

Carries and manufactures usually hold a database of unlocking codes based on the IMEI number (i.e. International Mobile Equipment Identity) of the phone.

When the carrier buys the phones from the manufacturer and when the software is installed on the phone they usually lock the phone to that particular carrier.

The unlocking database is handed over to the carriers once the purchase is completed.

Once the network-locked phone is sold to the customer, upon eligibility criteria, the customer can ask for the unlock code which is used to network unlock the phone.

Some phones come fully unlocked or factory unlocked which means there is never a code set on the phone and there isn’t a need to get an unlock code from the carrier.

These are phones typically purchased directly from the manufacturer.

Unlock code generator software from IMEI

Unlock codes can be generated with software based on the phone’s IMEI number. The software has a specific algorithm that takes the IMEI from the customer’s phone to retrieve the unlock code. Third-party unlock providers uses a similar algorithm that supports various phone models and carriers which is why they use a combination of IMEI and carrier or network provider details.

The software generates the code in the below format:

  • Defreeze (MCK) code
  • Network Unlock Key (NCK) / Network Unlock code
  • Service provider code key (SPCK)

These codes are passed on to the customer to get the phone unlocked.

Sometimes customers get confused between SIM unlock code and Subsidy unlock code but we are only referring to SIM unlock code for GSM.

Without the correct IMEI number, it is impossible to generate the code which is why the IMEI number is vital.

How do you get an IMEI number?

IMEI number of your phone can be found by entering a combination of keys *#06# on your phone keypad.

The IMEI number is used by a GSM (i.e Global System for Mobile) to identify phones (not subscribers) that connect to the carrier network.

Carrier or network providers can block any IMEI accessing their network.

The IMEI number includes information such as the origin, model, and the serial number of the device.

IMEI = 14 digits + 1 Check Sum Digit
IMEISV = 14 digits + 2 Digit Software Version Number (SVN)
IMEI + SV = 14 digits + 1 Check Sum Digit + 2 Digit Software Version Number (SVN)

IMEI format is universal and goes as ZZ-YYYYYY-XXXXXX-W (15 Digits) with variations mentioned above.

How to use the unlock code?

Once you have the unlock codes use the below steps to unlock your phone:

  1. Switch ON your Android phone with a non-compatible SIM Card inserted
  2. Wait for your Android phone to ask for “SIM Network Unlock PIN” or “Enter Network Lock Control Key” message on the screen
  3. Enter your MCK (Unfreeze Key) and hit the “UNLOCK” button (only if asked for).
  4. Enter your NCK (Network Code) and hit the “UNLOCK” button.

Once the phone is unlocked you can use it with any other carrier. More benefits of network unlocked phones can be found here.

How much does phone unlocking cost?

Phone unlocking costs will vary based on the Phone Model, Carrier, and Country it is locked to.

The older phone models can generally be unlocked for FREE however the latest model can cost more than $100.

Below is the table showing the approximate cost to unlock some of the popular brands:

Phone ModelCost (Carrier & Country Dependant)
Alcatel PhonesFREE – $60
AT&T Phones$25 – $80
Doro Phones$20 – $80
Google Phones$40 – $120
HTC Phones$20 – $60
LG PhonesFREE – $60
MaxonFREE – $40
Motorola Phones$20 – $60
Nokia PhonesFREE – $40
PanasonicFREE – $40
Samsung Phones$20 – $100
SiemensFREE – $40
Sony PhonesFREE – $120
T-Mobile Phones$20 – $80
ToshibaFREE – $40
VitelFREE – $40

Why do some unlock codes cost more than others?

The cost of unlocking is directly proportional to the availability of the network unlock codes.

Some carriers release the codes based on eligibility criteria or the age of the phone – these phones are typically cheaper to unlock.

In scenarios where the phones don’t meet the eligibility criteria, exclusive sales agreement or phones are newer models, the carrier doesn’t release those codes in which case the codes have to be obtained from the manufacturer.

The cost to obtain such a code is more expensive.

How long does a phone unlock take?

As mentioned previously in this article, the unlock code can be retrieved from the database or generated from software based on the phone IMEI number.

It could take longer for you to send the phone via post to get it unlocked rather than receiving the code via email.

Phone codes can be provided by carriers or third-party unlocking companies via email within 5 working days, however, it could also take up to 20 working days depending on the model phone model, carrier and country the phone is locked to.

Unlocking codes for iPhone

iPhones don’t have unlocking codes since Apple has full control over how phones are unlocked.

All phone IMEI is stored in the Apple database along with a lock status of the phone.

To unlock the iPhone the carrier has to send a request to Apple to unlock the phone, nobody can do this other than the carrier or Apple themselves. There are strict eligibility requirements due to the cost of the iPhone so it is important that the carrier is satisfied with the criteria. There are some third-party unlocking websites that can network unlock an iPhone.

Is the phone unlocked when the contract ends?

The phone is not unlocked unless you ask for the phone to be unlocked by the carrier e.g AT&T.

There are lots of criteria before the phone can be unlocked, only one of them is contract length.

Sometimes it also depends on how much money you spend on calls or other services which is why you don’t automatically get the phone unlocked.

Below are some of the criteria that the carrier will consider:

  • Paid for your phone in full
  • If the phone was purchased on an instalment plan active for 60 days
  • Contract has ended
  • The phone is not reported stole or lost

Final thoughts

The best way to get your phone unlocked is to approach your carrier as they are the legitimate providers of the unlock codes.

If you are unable to get the phone unlocked with your carrier you should consider using genuine third-party services such as us –