ISD code for calling India
India's ISD code is +91. To call an Indian landline from abroad: dial your country's international access code, then 91, then the STD code without the leading zero, then the local number.
For example, to call a Mumbai landline with STD code 022 from the United States: dial 011 (US international access code) + 91 (India's ISD code) + 22 (022 without the leading zero) + the 8-digit local number. From the United Kingdom, the international access code is 00 instead of 011, but the rest of the sequence — 91, then STD code without the zero, then local number — stays the same everywhere in the world.
Calling India on a mobile phone works differently from landlines: Indian mobile numbers don't use an STD code at all — dial +91 followed directly by the 10-digit mobile number, with no city code involved, since mobile numbers are assigned nationally rather than by geographic zone.
Calling from within India between cities uses a similar but shorter pattern: dial 0 (India's domestic trunk-call prefix) followed by the STD code including its leading zero, then the local number. So a Delhi caller dialing a Mumbai landline would dial 0-22-XXXXXXXX, whereas an international caller dials +91-22-XXXXXXXX without the domestic trunk prefix.
STD codes were originally introduced by India's telecom department to route trunk (long-distance) calls automatically through the public switched telephone network without needing an operator, and they remain in continuous use today for landline dialing, VoIP routing, and as a geographic reference point still printed on business cards, official documents, and directory listings even as mobile-first communication has become dominant.
Frequently asked
What's the difference between STD and ISD codes?
STD (Subscriber Trunk Dialing) codes are used for calls within India between cities. ISD (International Subscriber Dialing) is the country code used to call India from abroad — always +91.
Do I still need an STD code if I'm calling a mobile number?
No. STD codes apply only to landline numbers tied to a specific city. Mobile numbers in India are 10 digits with no city code, dialed directly with just +91 for international calls or the number alone domestically.
Why do some cities have 3-digit STD codes and others have 4 or 5?
Shorter codes (3 digits like 011 for Delhi, 022 for Mumbai) were assigned to the largest telecom exchanges historically handling the highest call volumes. Smaller cities and towns were assigned longer codes as the numbering plan expanded to accommodate more exchanges nationwide.
Can one STD code cover more than one city?
Yes — an STD code is assigned by telecom exchange coverage area, which can span a metro region including satellite towns, not strictly a single city's administrative boundary.
Is landline usage still common enough that STD codes matter?
Landline usage has declined sharply with mobile adoption, but STD codes remain relevant for business phone systems, government offices, older institutional numbers, VoIP services that emulate landline routing, and any legacy documentation still referencing them.
Do STD codes ever change or get reassigned?
Reassignment is rare but has happened historically during major telecom numbering-plan overhauls. For current, active use, STD codes are considered stable and are not casually changed.
What's the STD code format when dialing from a mobile phone within India?
The same domestic format applies — dial 0 followed by the STD code (including its own leading zero) and then the local number, regardless of whether you're calling from a mobile or landline.
Is there a difference between STD codes for government offices and private numbers?
No — STD codes are assigned purely by geographic telecom exchange, not by the type of subscriber. A government office and a private residence in the same city share the same STD code.
How do I find the STD code for a small town not listed here?
TRAI (Telecom Regulatory Authority of India) and BSNL publish comprehensive STD code directories covering every exchange in the country, useful for towns beyond the major cities listed on this page.
Why does my phone show a missed call with just a code and no name?
This is typically the STD code prefix of a landline number calling you — cross-referencing that prefix against an STD code list (like the one above) tells you which city the call originated from.
Is 91 the ISD code only for India, or shared with other countries?
+91 is uniquely assigned to India under the international E.164 numbering standard — no other country shares this specific country calling code.
About this STD code finder
This STD code finder and ISD code guide covers city dialing codes across India, the international access code for calling India (+91), and area codes for major cities including Delhi, Mumbai, Bengaluru, Chennai, Kolkata, and Hyderabad. Use it to find the STD code of any Indian city for landline dialing, or to look up the correct international dialing sequence when calling India from abroad.