The area codes in Pakistan consists of two to five digits; generally smaller the city, longer the prefix. All big cities have two-digit codes. The smaller towns might have six digital whereas big cities have seven digit numbers. Azad Kashmir telephone lines contain five digits. On 1 July 2009, telephone numbers in Karachi and Lahore were changed from seven digits to eight digits. This was accomplished by adding 9 to the beginning of all phone numbers that started with a 9 i.e. government and semi-government lines and adding 3 to all other lines.
Before May 2010, Pakistan used the international convention (ITU-T E-164) of a 4-digit mobile service provider code (e.g. 0300) and a 7 digit subscriber number (e.g. 1010101). Due to the large number of subscribers in the country, in May 2010, the PTA decided to introduce a 3-digit code for mobile service providers (e.g. 030) and an 8 digit number for the subscriber. The 11-digit number remained unchanged.