Country Codes Explained: Dialling, ISO & Currency Codes (2026)

Fill in almost any international form — a bank transfer, a shipping label, a sign-up page, a phone contact — and sooner or later it asks for a "country code." The trouble is that there is no single country code. The same country has a dialling code for phone calls, a two-letter code for web addresses and forms, a three-letter code for passports and banking, a numeric code for data systems, and a separate currency code for money. Mix them up and a payment bounces, a form rejects your entry, or a call never connects.

This guide clears up the confusion once and for all. We will go through each kind of country code — what it is, where it is used, and how to read it — then show how these codes show up inside phone numbers, web domains, IBANs, SWIFT codes and currencies, how to dial an international call correctly, and how to look any of them up in seconds.

The three families of "country code"

Almost every country code you will meet belongs to one of three families, each created by a different body for a different purpose:

• Dialling (calling) codes — the +44, +1, +20 you put before a phone number. Managed by the International Telecommunication Union (ITU).
• ISO 3166 country codes — the standardised two-letter (GB), three-letter (GBR) and numeric codes used by computers, banks, web domains and governments. Managed by the International Organization for Standardization (ISO).
• ISO 4217 currency codes — the three-letter money codes like USD, EUR and GBP. Also an ISO standard, but a separate one, because a country and its currency are different things.

Keep those three families straight and most of the confusion disappears. The rest of this guide takes each one in turn. If at any point you just need to find a specific code, the PAYATE Country Codes tool lists the dialling code, ISO codes and currency for every country in one place.

Dialling codes: the numbers before a phone number

When you see +44 20 7946 0958, the +44 is the country calling code for the United Kingdom. It tells the international phone network which country to route the call to before the national number takes over. These codes were designed by the ITU and grouped into world zones, which is why codes starting with the same digit tend to cluster geographically:

• Zone 1 — North America and much of the Caribbean, all sharing +1.
• Zone 2 — mostly Africa.
• Zones 3 and 4 — Europe.
• Zone 5 — Central and South America.
• Zone 6 — Southeast Asia and Oceania.
• Zone 7 — Russia and Kazakhstan, sharing +7.
• Zone 8 — East Asia and special services.
• Zone 9 — the Middle East and South Asia.

Codes are one, two or three digits long. Big, early-connected countries got the short ones — +1 for the US and Canada, +7 for Russia — while most countries have two digits (+44, +20, +49) and smaller nations often have three (+971 for the UAE, +880 for Bangladesh).

Why +1 covers so many countries

One quirk trips people up: +1 is not just the United States. It is the code for the entire North American Numbering Plan (NANP), which includes Canada and around twenty Caribbean nations. Each of those shares +1 but has its own three-digit area code, so +1 876 reaches Jamaica and +1 242 reaches the Bahamas. The country code and the area code together decide the destination.

How to dial an international call, step by step

A full international number has four parts, and getting the order right is what makes the call connect:

• The exit (international access) code — tells your phone network you are dialling abroad. It is 00 in much of the world, 011 in North America, or simply + on any mobile, which is the universal shortcut.
• The country code — 44 for the UK, 1 for the US, and so on.
• The national number — the area code plus the local number.
• The trunk prefix, dropped. Here is the catch most people miss: many countries write local numbers with a leading 0 (a "trunk prefix") that you must remove when dialling internationally. A London number written 020 7946 0958 becomes +44 20 7946 0958 — the leading 0 is dropped.

So to call that London number from the US you dial 011 44 20 7946 0958, or from a mobile anywhere simply +44 20 7946 0958. Forgetting to drop the trunk 0, or forgetting to add the country code, are the two most common reasons an international call fails.

ISO 3166: the codes computers and banks use

Phones use dialling codes; almost everything else — websites, forms, shipping, banking, government data — uses ISO 3166 country codes. This standard gives each country three different identifiers, and knowing which is which saves a lot of frustration.

Alpha-2: the two-letter code

The two-letter code (US, GB, DE, JP) is the one you meet most often. It is short, human-readable and everywhere:

• Web domains. Country top-level domains (ccTLDs) are built from the alpha-2 code: .us, .de, .jp. (The UK is the famous exception — it uses .uk rather than .gb for historical reasons.)
• Online forms. Country dropdowns almost always store the alpha-2 code behind the scenes.
• IBANs and SWIFT codes. The first two letters of both are the alpha-2 country code — DE at the start of a German IBAN, GB inside a UK SWIFT code.
• Language and locale tags. Codes like en-US or fr-FR use the alpha-2 country code after the language.

Alpha-3: the three-letter code

The three-letter code (USA, GBR, DEU, JPN) is more distinctive and is preferred where clarity matters more than brevity:

• Passports and travel documents use alpha-3 — your passport's machine-readable zone shows GBR or USA.
• International sport (the Olympics, FIFA) uses three-letter codes, though occasionally its own variants.
• Data systems and statistics often prefer alpha-3 because three letters are far less likely to collide or be misread than two.

Numeric: the three-digit code

ISO 3166 also assigns each country a three-digit numeric code (the UK is 826, the US 840). Numbers are language-independent and script-independent, so they suit systems that must work regardless of alphabet. You will see numeric country codes in some statistical datasets and inside standards that build on ISO 3166, including currency codes.

ISO 4217: currency codes

Money gets its own standard, ISO 4217, because a country and its currency are not the same thing — several countries share the euro, and some use another nation's currency entirely. A currency code is three letters, and the pattern is usually elegant: the first two letters are the country's alpha-2 code, and the third is the first letter of the currency name. So:

• USD — US dollar (US + Dollar).
• GBP — British pound (GB + Pound).
• JPY — Japanese yen (JP + Yen).
• EUR — the euro, one of the exceptions, named for the currency itself rather than a single country.

Each currency also has a numeric code, mirroring the way countries do. Currency codes are what you see on exchange-rate boards, in banking systems and on any form that handles money across borders, and using the right one removes all ambiguity about which "dollar" or "pound" you mean — there are many dollars (USD, CAD, AUD, HKD) and the three-letter code is how they are kept apart.

Where country codes hide inside other systems

Once you know the families, you start spotting country codes embedded all over the place:

• IBANs begin with the alpha-2 country code, which is how a bank instantly knows where an account is held.
• SWIFT/BIC codes carry the alpha-2 country code in characters five and six.
• Phone numbers carry the dialling code up front.
• Web addresses use the alpha-2 code as the ccTLD.
• Vehicle registration plates and international shipping use their own country identifiers, often derived from the ISO codes.
• Credit card and payment systems store the country of issue using ISO codes for routing and fraud checks.

This is why a single reference that ties them together is so handy: given one code, you often need another. The Country Codes tool maps all of them for every country, and because IBANs and SWIFT codes lean on the same alpha-2 codes, it pairs naturally with the IBAN Validator and the SWIFT / BIC Lookup when you are filling in international banking details.

Common confusions, cleared up

• UK vs GB. The ISO code is GB (and GBR), standing for Great Britain, yet the web domain is .uk. Both refer to the United Kingdom; the mismatch is historical. When a form wants the ISO code, use GB.
• Dialling code vs ISO code. +44 is for phones; GB is for everything else. A form asking for a "country code" in a phone field wants +44; in an address field it usually wants GB.
• Country vs currency. France's country code is FR, but its currency code is EUR, not FRF (which was the old franc). Shared currencies break the one-to-one assumption.
• Area code vs country code. Within +1, the area code (like 212 for New York) is part of the national number, not a separate country code.
• Leading zero. The 0 in a local number is a trunk prefix for domestic dialling and must be dropped when you add a country code for an international call.

Country codes for developers and form builders

If you build sign-up flows, checkouts or address forms, country codes are a daily companion, and a few practices save real pain:

• Store the alpha-2 code, display the name. Keep GB in your database and show "United Kingdom" to the user. Codes are stable; names and translations are not.
• Do not hard-code dialling codes to countries one-to-one. Remember that +1 maps to many countries, so a phone field needs the full number, not just the +1, to know the country.
• Validate against the standard, not a guess. Use the official ISO 3166 list rather than a home-made one, and update it when the list changes (countries occasionally change names or codes).
• Separate country from currency. Let users in the eurozone pick their country while the currency stays EUR; do not derive one rigidly from the other.

ISO 3166-2: codes for states, provinces and regions

The country codes everyone knows are only the first part of the standard. ISO 3166 has a second part, ISO 3166-2, that assigns codes to the subdivisions within a country — states, provinces, regions and territories. These are written as the country's alpha-2 code, a hyphen, and a local code: US-CA for California, GB-ENG for England, FR-75 for Paris. If you have ever wondered how a shipping system or a tax form knows exactly which state you mean regardless of spelling, this is often how. For anyone building address forms or logistics systems, ISO 3166-2 is the reliable way to identify a region without relying on free-text names, which vary by language and are easy to mistype. It pairs naturally with the top-level country code: the country tells a system which nation, and the subdivision code tells it which part.

Reserved and exceptional codes

A few codes do not map to a normal sovereign country, and knowing them prevents confusion:

• EU is an "exceptionally reserved" code for the European Union — useful because the EU is not a country but often needs to be identified in data and on forms.
• UK is reserved for the United Kingdom even though the official ISO code is GB, which is why you occasionally see UK used informally and GB used officially.
• Some codes are "transitionally reserved" after a country changes its name, so old data stays readable for a period before the code is retired.
• User-assignable ranges (such as codes beginning with X, like XK sometimes used for Kosovo) are set aside for private use and for places without a formal ISO code yet.

These edge cases are exactly why systems should use the official, maintained list rather than a hand-written one — the real world is messier than "one country, one code," and the standard carries that nuance so your software does not have to improvise.

E.164: the standard that formats phone numbers

There is a companion standard worth knowing on the phone side: E.164, the ITU format for international phone numbers. It specifies that a fully qualified number is written with a leading +, the country calling code, then the national number, with a maximum total of 15 digits. A number stored in E.164 format — +442079460958 — is unambiguous anywhere in the world, with no spaces, no leading zero and no local exit code to guess. This is the format apps and databases should store phone numbers in, because it travels cleanly across countries and makes validation straightforward: you know the first part is the country code and the rest is the national number. When you see a messaging app or a contacts system handle numbers from dozens of countries flawlessly, E.164 is usually why.

How country codes change over time

Country codes feel permanent, but they do change, and systems that assume otherwise eventually break. Countries are renamed, split, merge or newly recognised, and the standards bodies update the lists accordingly — a currency is replaced (as many European currencies were by the euro), a nation adopts a new short name, or a dialling code is reassigned. Because of this, the lists are maintained and versioned, and best practice is to refresh your copy periodically rather than hard-coding it once and forgetting it. The alpha-2 and alpha-3 codes are deliberately kept as stable as possible precisely so that databases do not have to be rewritten every time a name changes — another reason to store the code and display the name, rather than the other way around.

A quick reference: major country codes

To make the families concrete, here are some of the most-used countries with their dialling code, ISO alpha-2, alpha-3 and currency side by side — the kind of row the Country Codes tool gives you for every nation:

• United States — dialling +1, US / USA, currency USD.
• United Kingdom — dialling +44, GB / GBR, currency GBP.
• Germany — dialling +49, DE / DEU, currency EUR.
• France — dialling +33, FR / FRA, currency EUR.
• Egypt — dialling +20, EG / EGY, currency EGP.
• United Arab Emirates — dialling +971, AE / ARE, currency AED.
• Saudi Arabia — dialling +966, SA / SAU, currency SAR.
• India — dialling +91, IN / IND, currency INR.
• Japan — dialling +81, JP / JPN, currency JPY.
• Brazil — dialling +55, BR / BRA, currency BRL.
• Australia — dialling +61, AU / AUS, currency AUD.
• Canada — dialling +1, CA / CAN, currency CAD.

Notice the patterns the guide explained in action: the US and Canada share +1 but have different ISO and currency codes; Germany and France share the euro but have different everything else; and each currency code starts with the country's alpha-2 letters. One country, several codes — each doing its own job.

Country codes in APIs, data and everyday software

If you work with data of any kind, country codes are everywhere under the surface. Shipping and tax APIs expect ISO codes; analytics tools report traffic by country code; payment systems record the country of a card or bank using ISO codes; and content platforms serve the right language and currency based on them. Two habits make all of this painless: always use the standard codes as your keys rather than country names, and keep the country concept separate from language and currency, which change independently. Get that right and your systems speak the same unambiguous language as the banks, carriers and platforms they connect to — which is, after all, exactly why these standards were created.

Dialling within a country vs between countries

A number that works at home may not work from abroad, and vice versa, which trips up travellers constantly. Domestically, you usually dial the national format with its leading trunk zero and no country code — 020 7946 0958 in the UK. Internationally, you drop that zero and add the country code — +44 20 7946 0958. Some number types add their own wrinkles: toll-free numbers (like those starting 0800 or 1-800) often cannot be reached from outside the country at all, and premium or special-service numbers may be blocked internationally. The safe habit for any number you might need from abroad is to store it in full international form with the + and country code — that version works whether you are at home or on the other side of the world, which is exactly why phone contacts and apps standardise on it.

ccTLDs and the famous exceptions

Country-code web domains (ccTLDs) are built from the alpha-2 code — .de, .fr, .jp — but a few have taken on a life of their own, which is worth knowing when you judge a web address:

• .uk for the United Kingdom instead of the ISO .gb — the best-known mismatch, for historical reasons.
• .io (the British Indian Ocean Territory) has been widely repurposed by tech startups because "io" reads like "input/output."
• .tv (Tuvalu) is used worldwide for video and television sites, generating real revenue for a tiny nation.
• .co (Colombia) is marketed globally as a short alternative to .com.

The lesson is that a ccTLD tells you which country registered the domain family, not necessarily where the site or its owner is based. A .io address is rarely anything to do with the Indian Ocean. So treat a ccTLD as a hint about branding or registration, not as proof of location — the ISO code it is built on is reliable; how the domain is used is a separate matter.

How a country-code lookup saves time

Because the different codes for one country rarely sit together in everyday sources — your phone knows the dialling code, your bank knows the ISO code, your currency app knows the money code — a single reference that lines them all up is genuinely useful. Given a country, you can grab its dialling code for a call, its alpha-2 for a form or an IBAN, its alpha-3 for a document, and its currency for a payment, all at once. The Country Codes tool is built for exactly that: one searchable list tying every country to its calling code, ISO codes and currency, so you are never guessing whether the UK is GB or UK, or whether to drop the leading zero on a number. When you are filling in international banking details, it pairs naturally with the SWIFT / BIC Lookup and the IBAN Validator, which both rely on the very same two-letter country codes.

Frequently asked questions

What is the difference between a country code and a dialling code? "Dialling code" (like +44) is specifically for phone calls. "Country code" more often means the ISO 3166 letters (GB, GBR) used by computers, banks and websites. Context decides which a form wants.

Why is the UK's code GB and not UK? The ISO standard uses GB (Great Britain). The .uk web domain is a separate, historical choice. Both mean the United Kingdom.

What does the + before a phone number mean? It is the universal stand-in for the international exit code. On a mobile, typing + works from any country, so you never have to remember whether the local exit code is 00 or 011.

Do I keep the leading zero when dialling internationally? No. Drop the leading 0 trunk prefix and replace it with the + and country code. 020 7946 0958 becomes +44 20 7946 0958.

Is the currency code the same as the country code? No. Currency codes (ISO 4217, like USD) are separate from country codes (ISO 3166, like US), because countries can share a currency and the two change independently.

Why do IBANs and SWIFT codes contain country codes? So any bank, anywhere, can instantly identify the country an account or institution belongs to. Both use the ISO 3166 alpha-2 code.

Can two countries share a dialling code? Yes. +1 covers the US, Canada and many Caribbean nations, and +7 covers Russia and Kazakhstan. Area codes distinguish them.

What is the difference between alpha-2 and alpha-3 codes? Alpha-2 is two letters (GB) used in domains, forms, IBANs and SWIFT codes; alpha-3 is three letters (GBR) used in passports, sport and data where extra clarity helps. Same country, two codes for different contexts.

Why is .io used by tech companies if it belongs to the Indian Ocean? It is a repurposed ccTLD — "io" reads like input/output, so startups adopted it for branding. The ccTLD shows which country registered the domain family, not where the site is based.

What is E.164? The international standard format for phone numbers: a +, the country code, then the national number, up to 15 digits total. Storing numbers this way makes them unambiguous worldwide.

Do country codes ever change? Yes — countries are renamed, split or newly recognised, so the lists are maintained and versioned. Store the code and display the name, and refresh your list periodically.

Which code does an online form usually want? In a phone field, the dialling code (+44); in an address or country field, the ISO alpha-2 code (GB). Context decides.

Even more country codes you may meet

The three families cover almost everything, but a few other country-code systems exist for specialised uses, and recognising them rounds out the picture. International sport uses three-letter codes that mostly follow ISO alpha-3 but occasionally differ — which is why a team's code at a global event may not exactly match its ISO code. Vehicle registration and international driving documents use their own distinguishing signs for countries. Aircraft and ship registrations carry nationality prefixes. And various statistical and postal systems layer their own identifiers on top of the ISO base. You rarely need these day to day, but they explain why you occasionally see a country abbreviated in a way that does not match the GB/GBR you expected. The reassuring part is that nearly all of them trace back to the same ISO 3166 foundation, so once you understand the core families, the specialised ones are easy to place. When you just need the everyday codes — dialling, ISO letters and currency — one lookup in the Country Codes tool gives you all of them together.

Key takeaways

"Country code" is really several different codes for different jobs. Dialling codes (+44, +1) route phone calls and are grouped into ITU world zones. ISO 3166 gives each country a two-letter code (GB) used in domains, forms, IBANs and SWIFT codes, a three-letter code (GBR) used in passports and data, and a numeric code for systems. ISO 4217 handles currencies (GBP, USD) separately, because a country and its money are not the same. When dialling abroad, add the + and country code and drop the local leading zero; when filling a form, give the alpha-2 code; and when in doubt about any of them, look them all up at once with the Country Codes tool.