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New Delhi: We all dial mobile numbers every day, but have you ever wondered why these numbers in India are always 10 digits long? If even one digit is missing or added, the number becomes invalid. What’s the problem if the number is 8, 9, or 11 digits?

Actually, the 10 digits in a mobile number are the result of a carefully thought-out system. Let’s find out why mobile numbers always have 10 digits and what they mean.

What’s the math behind it?

First, let’s understand the math. In fact, each country determines the number of phone numbers based on its population. The total number of numbers available in a 10-digit number system is 10 billion. This is a huge number, enough to assign unique numbers to any country’s population.

If numbers were 9 digits, the total number available would be only 1 billion, which is insufficient for a country with a huge population like India. Meanwhile, 11-digit numbers would create 100 billion possibilities, which would likely be excessive and time-consuming to dial. Therefore, after careful consideration, a 10-digit mobile number was established for India.

What do these 10 digits mean?

A mobile number is not just an identity, it is also an ‘address’ that tells telecom networks where to route calls. In India, the structure of a mobile number is as follows:

The first four or five digits are the ‘converter code’, which identifies the mobile network operator and telecom circle.

The remaining six or five digits are the subscriber’s unique number.

Have mobile numbers in India always been 10 digits?

Telephone numbers in India used to be six or seven digits long until the 1990s. However, after 2000, the mobile revolution took hold, and the number of subscribers skyrocketed. Furthermore, the population was also growing rapidly. Therefore, the old numbering system didn’t have enough numbers for the new subscribers. To address this challenge, the Telecom Regulatory Authority of India (TRAI) devised a new plan, and around 2003, 10-digit mobile numbers were implemented nationwide.