Bank Number Formats Around the World

IBAN System (80+ Countries)

The International Bank Account Number (IBAN) is the most widely adopted bank account identification system in the world. Defined by the ISO 13616 standard, IBANs are used in over 80 countries across Europe, the Middle East, North Africa, and parts of Latin America and the Caribbean. The system was originally developed to facilitate cross-border payments within Europe but has since been adopted far beyond the continent.

An IBAN consists of up to 34 alphanumeric characters, structured as follows:

• Country code — Two letters identifying the country (e.g., DE for Germany, FR for France)
• Check digits — Two digits calculated using a modulo-97 algorithm (ISO 7064). These catch transcription errors before the payment is sent, preventing misrouted transfers.
• Basic Bank Account Number (BBAN) — The remaining characters, which vary by country and typically include the bank code, branch code, and account number.

For example, a German IBAN like DE89 3704 0044 0532 0130 00 breaks down into: country code DE, check digits 89, bank code 37040044, and account number 0532013000.

The built-in check digit algorithm is one of the IBAN system's greatest strengths. It catches over 99% of single-character errors and transposition mistakes. You can validate any IBAN using our IBAN checker. For a deeper explanation of the format, see our guide on what is an IBAN.

US System: Routing Numbers

The United States does not use the IBAN system. Instead, US banks are identified by 9-digit ABA routing numbers, developed by the American Bankers Association in 1910. These routing numbers are used to direct payments through the US domestic banking network.

There are two types of routing numbers that serve different purposes:

• ACH routing numbers — Used for electronic transfers through the Automated Clearing House network, including direct deposits, bill payments, and bank-to-bank transfers. ACH transfers typically settle in 1–2 business days.
• Wire routing numbers — Used for same-day domestic wire transfers processed through the Federal Reserve wire system (Fedwire). Some large banks have different routing numbers for ACH and wire transfers.

The first two digits of a routing number indicate the Federal Reserve district where the bank is located. There are 12 Federal Reserve districts, numbered 01 through 12, covering the entire country. The routing number also includes a check digit calculated using a weighted-sum algorithm for error detection.

Validate any US routing number using our routing number checker. For more detail on the format, see our routing number glossary entry.

UK System: Sort Codes

The United Kingdom identifies banks and branches using 6-digit sort codes, typically displayed in the format XX-XX-XX (three pairs of digits separated by hyphens). Each sort code uniquely identifies a specific bank branch within the UK banking system.

A UK bank account is identified by the combination of a 6-digit sort code and an 8-digit account number. For domestic payments within the UK (through Faster Payments, BACS, or CHAPS), only the sort code and account number are needed.

The first two digits of the sort code generally indicate the bank. For example, sort codes starting with 20 belong to Barclays, while those starting with 60 belong to NatWest.

While the UK also has IBANs (a UK IBAN is 22 characters, starting with GB), they are primarily used for receiving international transfers. UK domestic banking runs entirely on the sort code and account number system. Verify any sort code using our sort code checker.

SWIFT/BIC (Universal)

The SWIFT/BIC (Bank Identifier Code) system operates alongside every national banking system. While IBANs, routing numbers, and sort codes identify specific accounts or branches, a SWIFT code identifies the financial institution itself on the global SWIFT messaging network, which connects over 11,000 financial institutions in more than 200 countries.

A SWIFT/BIC code is either 8 or 11 characters long:

• Characters 1–4: Bank code — Identifies the institution (e.g., DEUT for Deutsche Bank)
• Characters 5–6: Country code — ISO 3166-1 alpha-2 country code (e.g., DE for Germany)
• Characters 7–8: Location code — Identifies the city or region (letters or digits)
• Characters 9–11: Branch code (optional) — Identifies a specific branch. If omitted (8-character code), it refers to the bank's head office. The code XXX in positions 9–11 also indicates the head office.

For international wire transfers, you almost always need both the account identifier (IBAN, routing number, or sort code) and the SWIFT/BIC code. Validate any SWIFT code using our SWIFT/BIC validator. For a deeper dive, see our guide on what is a SWIFT/BIC code.

Other National Systems

Several major economies use their own domestic bank identification systems that do not follow the IBAN standard:

Comprehensive Comparison

The following table compares all major bank number formats in use today:

As the table shows, the IBAN and ABA routing number systems are the only major formats that include a built-in checksum for error detection. This is one reason why IBAN has become the international standard — the check digit algorithm catches typos before they cause failed payments.

Convergence Trends

The global landscape of bank number formats is gradually converging toward greater standardisation, driven by three major trends:

• IBAN adoption continues to expand — New countries continue to adopt the IBAN standard. Recent adopters include countries in Latin America, Africa, and Central Asia. The ISO 13616 standard provides a framework that any country can implement while maintaining its own domestic BBAN structure. However, major economies like the US, Canada, Australia, and Japan have shown no indication of adopting IBAN.
• SWIFT GPI is modernising cross-border transfers — SWIFT Global Payments Innovation (GPI) has dramatically improved the speed and transparency of international wire transfers. Over 90% of GPI payments are credited to beneficiary accounts within 24 hours, and the system provides end-to-end tracking. This reduces the friction caused by different national formats, even though it does not eliminate the formats themselves.
• ISO 20022 migration is standardising messaging — The global financial industry is migrating to ISO 20022, a universal messaging standard for financial transactions. SWIFT began its migration to ISO 20022 for cross-border payments in March 2023. ISO 20022 uses structured, data-rich messages that can accommodate any national bank number format while providing consistent fields for account identification, bank identification, and payment details. This does not replace national formats but creates a common language for transmitting them across borders.

Despite these convergence trends, national bank number systems remain deeply embedded in domestic payment infrastructure. Full standardisation on a single global format remains unlikely in the foreseeable future, making it essential to understand the specific requirements of each country you send money to.

Frequently Asked Questions

Will the United States ever adopt IBAN?

There are currently no plans for the US to adopt the IBAN system. The US banking infrastructure is built around the ABA routing number system, which is deeply integrated into every aspect of domestic banking — from cheques and direct deposits to wire transfers and ACH payments. The cost and complexity of migrating the world's largest banking system to IBAN would be enormous, and the Federal Reserve has not signalled any interest in such a transition. For international transfers involving US accounts, the combination of ABA routing number, account number, and SWIFT code continues to be the standard.

Can I use an IBAN to send money to a US bank account?

No. US banks do not have IBANs. To send money to a US bank account, you need the recipient's ABA routing number (9 digits), their account number, and the bank's SWIFT/BIC code for international transfers. If someone asks you for an IBAN and you have a US account, explain that the US does not use the IBAN system and provide the routing number and account number instead.

What bank number format does China use?

China uses the CNAPS (China National Advanced Payment System) code, also known as the China Union Pay number, to identify banks and branches. A CNAPS code is 12 digits long, where the first 3 digits identify the bank, the next 4 identify the city, and the remaining 5 identify the branch. China does not use IBANs. For international transfers to China, you need the CNAPS code, the recipient's account number, the bank's SWIFT code, and a purpose of payment (mandatory due to China's capital controls).

Do all countries have checksums in their bank numbers?

No. Only a few systems include built-in checksums for error detection. The IBAN system uses a modulo-97 check digit algorithm that catches over 99% of transcription errors. US ABA routing numbers use a weighted-sum checksum. However, UK sort codes, SWIFT/BIC codes, Indian IFSC codes, Australian BSB numbers, Canadian transit numbers, and Japanese Zengin codes do not include checksums. For systems without built-in checksums, validation relies on checking the format and verifying the code against a registry of known valid codes.

Validate Any Format

No matter which bank number format you are working with, validating the details before initiating a transfer is the best way to avoid errors, delays, and lost funds. BankCheck supports validation for the most widely used formats:

• IBAN validator — Validate IBANs from 80+ countries
• US routing number checker — Verify 9-digit ABA routing numbers
• UK sort code checker — Validate 6-digit UK sort codes
• SWIFT/BIC validator — Verify SWIFT codes for banks worldwide

Or use our universal bank number checker — paste any bank number and we will automatically detect the format, validate it, and show you a detailed breakdown. All validation runs client-side, so your data never leaves your browser.