What is an ARN (Acquirer Reference Number)? How to track refunds and payments

Key takeaways

• An Acquirer Reference Number (ARN) is a unique 23-digit code that tracks card transactions as they move between the acquiring bank, payment network, and issuing bank.

• ARNs help you trace refunds, resolve chargebacks, and give customers clear answers about their payment status.

• With Airwallex, you can find ARNs directly in your payment details and manage card transactions across 180+ countries from one platform.

Acquirer Reference Numbers (ARN) are unique 23-digit tracking codes that follow card transactions through the entire payment network, from your acquiring bank to the customer’s issuing bank.

With an ARN, you can see exactly where a payment or refund is at any point. That means faster answers for customers, stronger evidence if you need to contest a chargeback, and less time spent chasing payment queries.

In this article, we’ll cover what an ARN is, how it’s structured, where to find it, and how to use it for refunds, chargebacks, and cross-border payments.

What is an ARN number?

As we've already covered, an Acquirer Reference Number (ARN) is a unique 23-digit identification code assigned to every credit or debit card transaction as it moves through the credit card processing network.

Try to think of it like a parcel tracking number that follows a package across multiple courier handoffs, from the warehouse to the sorting centre to your door. An ARN does the same job for payments.

ARN's link the merchant’s bank, the payment processor, and the card issuer together so the transaction can be traced from start to finish.

Using an ARN, you can see exactly where a payment, refund, or transfer is at any point in the process. Unlike internal transaction IDs, which stay inside your payment platform, ARNs are recognised across the wider payment network, including Visa, Mastercard, and other card schemes. That makes it much easier to manage payments, deal with customer queries, and get faster answers when something needs checking.

Now that you know what an ARN is, let’s look at how it’s structured.

How a 23-digit ARN is structured

Every ARN follows a standardised format, and each segment carries specific information about the transaction. Here’s what each part of an ARN usually represents:

Example ARN: 45012345678901234567890

• Card network indicator: The first digit shows the card network. For example, 4 indicates Visa, whilst 5 indicates Mastercard. So right away, you can tell which network processed the transaction.

• Acquirer BIN: The next six digits are the Bank Identification Number (BIN) of the acquiring bank, which is the bank that processed the transaction on behalf of the merchant. This part tells you exactly which bank handled the payment.

• Julian date: The following four digits show the transaction date in Julian format: one digit for the last digit of the year, and three digits for the day of the year. For example, “5125” means the 125th day of a year ending in 5 (roughly early May).

• Transaction sequence number: The remaining digits make up a unique identifier for that specific transaction. This is what makes each ARN globally unique, so no two transactions will ever share the same full ARN.

Just bear in mind that the exact format can vary slightly between card networks, so it’s best to treat this as a general guide.

The main point is that every segment has a purpose, which is what makes the ARN such a useful tool for tracing payments across the whole network.

What are ARNs used for?

When you’re trying to sort out a payment issue, speed and clarity matter. That’s where an ARN can make a real difference. It gives you a way to track a card transaction through the banking system and quickly see where it stands.

Say a customer emails asking where their refund is. Here’s how the ARN helps:

• Track payments, refunds, and transfers across different banks. The ARN follows the transaction through every handoff, so you’re not left guessing which institution is holding things up.

• Find out why a refund’s been delayed and fix it faster. Instead of waiting for vague updates, you can pinpoint exactly where the refund is sitting in the process.

• Resolve customer disputes by showing proof that a payment was processed. The ARN acts as evidence that a transaction or refund really went through.

• Work more closely with banks and payment providers when something needs investigating. Banks recognise ARNs across the network, so everyone’s speaking the same language.

• Give customers reassurance that their payment or refund is moving as it should. You can share the ARN so they can check directly with their bank.

• Reduce chargeback losses. If you can prove a refund was issued using the ARN, you’re in a much stronger position to contest a dispute before it costs you money. For added protection, some businesses also invest in

  chargeback insurance.

Using the ARN helps you avoid long back-and-forth conversations and spend less time chasing payment queries.

Here are three more in-depth examples of how you can use an ARN to resolve common payment issues:

1. Tracking refunds and payments: When a refund is issued, it doesn’t arrive instantly. Card refunds usually take 5–10 business days to reach the customer’s account. The ARN lets you, and the customer, follow that refund from your acquiring bank, through the card network, to the issuing bank. So, for example, let's say a customer says their refund hasn’t arrived after seven days. You pull the ARN from your payment dashboard, contact your acquiring bank, and find out the refund is pending at the issuing bank’s end. Now you can tell the customer exactly what’s happening and when to expect the funds. No more guesswork.

2. Resolving disputes and chargebacks: ARNs are key evidence in payment disputes. If a customer files a chargeback claiming they never received a refund, you can provide the ARN to show that the refund was processed and delivered to their issuing bank. That can stop a chargeback from escalating and save you the fees that come with it. We’ll cover this in more detail in the chargebacks section below.

3. Giving customers clear answers: Instead of waiting and wondering when a refund will arrive, customers can use the ARN to check directly with their bank. When you share the ARN with them, you’re giving them control and visibility over their own transaction. That cuts down confusion, reduces support queries, and builds trust by showing that your business takes their concerns seriously.

Knowing what ARNs are used for is helpful, but it also helps to see how they differ from other reference numbers you’ll come across.

ARN number vs. other payment identifiers

If you’ve ever looked at a transaction record and seen multiple reference numbers, you’re not alone. Here’s how they differ:

When to use each identifier

• ARN: Use when tracing a payment or refund across banks, or when responding to a chargeback.

• Transaction ID: Use for internal lookups in your payment dashboard or when referencing orders within your own systems.

• Authorisation code: Use to confirm a transaction was approved at the point of sale, or when a customer queries whether their payment went through.

Now that you know which identifier to use when, let’s look at where to find your ARNs.

Where to find an ARN number

You can usually find the ARN for a transaction in your payment gateway portal or merchant dashboard. It often shows up alongside the payment status or refund confirmation details. If it isn’t visible straight away, your payment processor can pull it up for you.

For customers, the ARN isn’t always shared automatically. If a customer asks about the status of a refund or payment, you can retrieve the ARN from your system and pass it on to them. Some banks also include ARN details in transaction reports, but the quickest route is usually through the merchant.

Keeping easy access to your ARNs helps you move quickly when customers need updates, or when you need to follow up with your bank or payment provider.

Finding the ARN in Airwallex

In Airwallex, you can find the ARN on the payment details page. Just go to the transaction you need, and the ARN will be displayed alongside the other payment details.

How to check an ARN number

Once you have the ARN, here’s how to use it:

• Find the ARN in your payment dashboard. Locate the transaction and copy the 23-digit code.

• Contact your acquiring bank or payment processor. Give them the ARN to get a status update on where the payment or refund sits in the network.

• Or, share it with the customer. They can give the ARN to their issuing bank to trace the transaction themselves.

How ARNs help with chargebacks and cross-border payments

ARN tracking becomes especially useful in two situations: when you’re contesting a chargeback, and when you’re dealing with international transactions that pass through multiple banks.

Using ARNs to fight chargebacks

Here’s a scenario: a customer files a chargeback claiming they never received a refund. Without evidence, you’d have very little to stand on. But if you have the ARN, you can pull up the transaction record, show that the refund was processed and delivered to the issuing bank, and contest the dispute with solid proof.

When a customer disputes a £500 charge, having the ARN ready can be the difference between winning and losing that case. Keeping your ARN records organised supports faster reconciliation and doesn’t just save time. It can save your business significant money on dispute fees.

Tracing payments across borders

Cross-border card payments often involve more intermediaries than domestic ones. A payment might travel from an acquiring bank in one country, through the card network, to an issuing bank in another. The ARN follows the transaction across all of them, so you have visibility at every stage.

For example, say you’re a UK merchant refunding a customer in Japan. The ARN traces that refund from your UK acquiring bank, through the card network, to the Japanese issuing bank. If the customer asks where their money is, you can tell them exactly where it’s sitting in the process.

Airwallex processes payments across 180+ countries, and having ARN visibility across these transactions helps businesses track international refunds and resolve disputes faster, without the guesswork and cross-border fees that come with international complexity.

Track your card payments with Airwallex

Whether you’re tracing a refund ARN or contesting a chargeback, having the right tools matters. Airwallex gives you transaction visibility directly in your WebApp, with ARNs available on every payment details page. Add in global acquiring in 35+ markets and support for 160+ local payment methods, and you can manage card payments across borders from one platform and sort out issues faster when they come up.

Create a free account to see how Airwallex can help you track and manage your card transactions globally.

Frequently Asked Questions (FAQs)

What is a 23-digit ARN number?

A 23-digit ARN is a unique identification code assigned to every card transaction, with each segment encoding specific information like the card network, acquiring bank, transaction date, and a unique sequence number. That structure makes it possible to trace a payment across the entire card network, from the merchant’s bank to the customer’s issuing bank.

How do I check an ARN number?

You can check an ARN by finding it in your payment dashboard or merchant portal, then sharing it with your acquiring bank or payment processor to get a transaction status update. Customers can also give the ARN to their issuing bank to trace a refund directly.

Is the ARN the same as a transaction ID or order number?

No. A transaction ID or order number is specific to your payment platform or website. The ARN is a network-level tracking code used across banks to trace card payments.

How long does it take to receive an ARN for a transaction?

An ARN is usually generated once the transaction is fully processed by the payment network. This usually happens within a few hours of the original payment or refund.