What Is a BIN Number and How Does It Work?

What is a BIN number?

A Bank Identification Number (BIN) is the first 6 to 8 digits of a payment card number, and it identifies the institution that issued the card. Every card an issuer releases under the same product range shares the same BIN.

The digits after the BIN are unique to the cardholder's account. The full card number is called the Primary Account Number (PAN).

How does a BIN differ from an IIN, PAN and BIC?

BIN and IIN are the same digits under 2 names, while PAN and BIC are different things. The formal ISO/IEC 7812 standard uses Issuer Identification Number (IIN).¹

How do you read a BIN number?

A BIN is not random, because each position in the card number carries a meaning. The first digit shows the broad industry, the next digits identify the issuer and product, and the last digit validates the number.

Which card network does the first digit show?

The first digit usually points to the card network, but it is a hint, not proof. Mastercard also issues from a 2-series range, 222100 to 272099, alongside its 5-series.²

Use an authorised BIN table when you need a certain answer, not a guess from the first digit.

What types of BIN exist?

BINs fall into 6 common types, based on how the card is used and how it is funded. The use is consumer or commercial, and the funding is prepaid, debit or credit.

For how corporate cards work in Hong Kong, see Aspire's guides to the corporate credit card and how to get one.

What is a shared BIN versus a dedicated BIN?

A dedicated BIN is assigned to 1 organisation, while a shared BIN is used by several organisations under the same licensed framework. Cards on a shared BIN draw their leading digits from the same range.

The underlying program may serve several fintech brands behind the scenes. Both setups are common in modern card programs.

Why did BINs expand from 6 to 8 digits?

BINs expanded because demand for issuer codes outgrew the 6-digit format. Mastercard says rising BIN demand, partly driven by tokenisation, prompted the change.³

The change happened in stages rather than on 1 date, as the table shows.

Do 6-digit BINs still exist?

Yes, 6-digit and 8-digit BINs coexist. Visa says merchants and service providers should be ready to support both lengths at once.⁴

A single prefix cannot be both, because once a 6-digit BIN is split into 8-digit BINs, the 6-digit one ceases to exist.⁴ The card number length does not change, so your cards keep working.

What is a BIN number used for?

A BIN does far more than name a bank, because it drives how a transaction is routed and checked. The payment network reads the BIN first to decide which institution receives the authorisation request.

How does a BIN affect a Hong Kong business?

BIN handling affects 4 everyday jobs: reconciliation, fraud checks, data storage and judging card rewards. The list shows what to do for each.

• Reconcile by card type. Tag physical and virtual cards separately when you match transactions with your books, especially with many virtual cards across staff and vendors. Aspire's guide to virtual versus physical cards explains the difference, and expense management matches each card's spend to receipts.
• Use an authorised BIN table. Visa says BIN tables found on the internet are only about 30% accurate, so use authorised tables or Visa's BIN Attribute Sharing Service.⁴
• Store as few digits as you can. PCI DSS limits display to the first 6 and last 4 digits unless there is a documented business need, and Mastercard recommends storing the fewest digits possible.³ ⁵
• Read rewards claims by card type. Commercial and consumer BINs typically carry different interchange and rewards structures. Compare cards in Aspire's guide to cashback cards for Hong Kong businesses.

What changed for systems that read the BIN?

Any system that reads BINs must handle both 6-digit and 8-digit values. Visa warns that acquirers and processors that were not ready risk failed transactions and longer resolution times.⁴

If you accept cards online, confirm with your payment provider that routing, fraud scoring and reports use the full BIN. If you issue cards, you control the BIN only through your issuer or program manager. Aspire's corporate card gives teams virtual and physical cards without any BIN setup on your side.

Why Hong Kong Businesses Choose Aspire

Understanding what sits behind a card number is one thing, and managing card spend across a growing team is another, which is where Aspire helps.

💱 FX spreads from 0.18%, up to 3x cheaper than traditional banks. This applies across 130+ countries and 40+ currencies through Aspire's multi-currency account. It's useful for anything from paying overseas suppliers to settling international payments without losing margin to markup.

💰 1.2% unlimited cashback applies on every corporate card transaction, with no monthly cap. It kicks in automatically on eligible spend, with no minimum threshold to hit first. Over time, it quietly turns routine business spend into working capital.

🌐 Local transfer network, not multi-hop SWIFT chains, is how Aspire routes most payments. This means faster settlement and fewer intermediary fees eating into your payment before it reaches the recipient. It also reduces the chance of funds being held up for review at a correspondent bank along the way.

💸 Fixed USD 8 inbound SWIFT fee, tracked end-to-end with SWIFT GPI, applies when SWIFT is the right rail for your payment. There are no surprise deductions from correspondent banks along the way, so the amount you're quoted is the amount that arrives. You can also download payment confirmation instantly from the app, without calling the bank.

⚡ Approved in as little as 1 business day, with no branch visits and no paperwork stacks. Applications are completed entirely online, from document upload to approval. There's no waiting weeks on a relationship manager to call you back.

Open a free multi-currency business account built for Hong Kong SMEs, or explore how Aspire's corporate card fits into your day-to-day spend.