What is an STD Code?

Complete guide to Subscriber Trunk Dialling codes — India's domestic area codes for city-to-city calling

What is an STD Code?

STD stands for Subscriber Trunk Dialling. An STD code is a numeric prefix (area code) assigned to each city, town, or region in India by the Department of Telecommunications (DoT). It identifies the geographic destination of a landline call and is required when making long-distance domestic calls.

STD codes in India range from 2 to 4 digits (excluding the leading 0). Major metros have shorter codes (e.g. 11 for Delhi, 22 for Mumbai), while smaller towns have longer 3- or 4-digit codes. The leading 0 is a trunk prefix — it is dialled domestically but dropped when calling from abroad.

How to Dial Using an STD Code

Format: 0 + [STD Code] + [Local Number]

  1. Dial 0 (trunk access code for domestic long-distance)
  2. Enter the STD code of the destination city
  3. Dial the local landline number

Example: To call a Bangalore landline (STD 080, local number 2345 6789) from Delhi: dial 080-2345 6789

From abroad: Drop the leading 0 and add India's ISD code (+91): +91 80 2345 6789

Common STD Codes in India

CitySTD Code
New Delhi011
Mumbai022
Kolkata033
Chennai044
Bangalore080
Hyderabad040
Ahmedabad079
Pune020
Jaipur0141
Lucknow0522
Chandigarh0172
Kochi0484
Bhopal0755
Patna0612
Guwahati0361
Thiruvananthapuram0471
Coimbatore0422
Visakhapatnam0891

STD Code Structure in India

  • 2-digit codes (0XX): Six major metros — Delhi (011), Mumbai (022), Kolkata (033), Chennai (044), Bangalore (080), Hyderabad (040)
  • 3-digit codes (0XXX): State capitals and large cities — Pune (020), Ahmedabad (079), Jaipur (0141)
  • 4-digit codes (0XXXX): Smaller cities and towns — Shimla (0177), Ooty (0423), Manali (01902)

The total length of STD code + local number always adds up to 10 digits (excluding the leading 0). Shorter STD codes have longer local numbers and vice versa.

STD vs ISD Codes

  • STD codes — for domestic long-distance calls within India (city-to-city). Prefixed with 0.
  • ISD codes — for international calls between countries. India's ISD code is +91.
  • When calling India from abroad, replace the leading 0 of the STD code with +91.

Learn more about ISD codes →

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Frequently Asked Questions

What is an STD code in India?▼
STD stands for Subscriber Trunk Dialling. An STD code is a numeric area code assigned to a city or region in India that must be dialled before the local landline number when making a long-distance domestic call.
How do I dial an STD number from a mobile phone?▼
From an Indian mobile phone, simply dial the full 10- or 11-digit number including the STD code with leading zero. For example, to call a Delhi landline: 011-2345 6789. No special trunk prefix is needed on mobile.
What is the STD code of Delhi?▼
The STD code of Delhi (New Delhi) is 011. To call a Delhi landline from another city, dial 011 followed by the 8-digit local number.
What is the STD code of Mumbai?▼
The STD code of Mumbai is 022. To call a Mumbai landline, dial 022 followed by the 8-digit local number.
What is the difference between STD and ISD codes?▼
STD codes are used for long-distance domestic calls within India (city-to-city), while ISD (International Subscriber Dialling) codes are used for international calls between countries. For example, 011 is Delhi's STD code, and +91 is India's ISD code.
Are STD codes still used in India?▼
Yes. STD codes are still used for landline-to-landline calls and are embedded in the 10/11-digit dialling format. With mobile phones, the STD code is included automatically in the number. Telecom operators and BSNL/MTNL directories still reference STD codes for routing.