AVS Mismatch: What It Means and How to Fix It

An AVS mismatch means the billing address entered at checkout did not match the address the card issuing bank has on file. The card network did not decline anything. It returned a letter code describing how well the address matched, and something further down the chain decided what to do about it.

That distinction matters, because the fix depends entirely on who made the decision. It also matters for a reason almost nobody explains to merchants: every one of those address checks is a billable event, and a checkout that produces a lot of mismatches is quietly expensive.

What an AVS mismatch actually is

The Address Verification Service compares two things at the moment a card is authorized: the numeric parts of the billing address submitted with the transaction, and the numeric parts of the address on file at the issuing bank. It only ever looks at numbers. The street number and the postal code. It does not read the street name, the city or the state.

The issuer returns a single letter. That letter is not an approval or a decline. It is a description. The transaction can be approved with a total mismatch, and it can be declined with a perfect match, because the approval decision and the address decision are two separate things.

So when a transaction fails on an AVS mismatch, one of three parties made that call: the issuing bank as part of its own risk scoring, the payment gateway acting on rules configured in the account, or the merchant, through settings someone chose at some point and probably has not looked at since.

What each AVS code means

The codes below are the standard set returned by the card networks. Your gateway may map them to its own labels, and American Express uses several codes that check the cardholder name as well, which Visa and Mastercard do not.

The three codes worth paying attention to are U, R and S. None of them is a mismatch. They mean no comparison happened at all, usually because the issuer does not participate or its system was down. If your gateway is set to decline on anything that is not a Y, you are turning away customers whose banks simply do not answer the question.

Why good customers get a mismatch

Most mismatches are not fraud. In our experience reading merchant statements, the ordinary explanations come up far more often than the criminal ones:

• The customer typed the shipping address instead of the billing address. AVS only ever checks the billing address on file at the bank.
• The card is a corporate or purchasing card and the address on file is the company head office, not the office the buyer sits in.
• The customer moved and updated the delivery address with the retailer but never told the bank.
• The address has an apartment, suite or unit number that the checkout form split into a second line the gateway did not pass.
• The issuer is outside the United States. Most non US banks return G or I, because AVS is largely a US and UK system.
• The billing address is a PO box or a rural route that the issuer stores in a format the comparison cannot read.

If you are the cardholder

Enter the address exactly as it appears on your card statement, not the address where you want the order delivered. If that fails, check the postal code first, since it carries more weight than the street in most gateway rules. If it still fails, call the number on the back of the card and ask what billing address the bank has on file. It is often an old one.

Do not keep retrying. Every attempt creates a new authorization hold on the card, and several failed attempts can tie up more of your available credit than the purchase itself.

If you are the merchant

Start by finding out who is actually declining the transaction, because the fix is different in each case.

Check your gateway rules first

Log into your gateway and look at the AVS filter settings. Many accounts are configured to reject anything other than a full match, often because that is how the reseller left them on the day the account was opened. A rule that rejects Z and A is rejecting customers whose postal code matched perfectly. A rule that rejects U, R, S or G is rejecting customers whose bank never ran the check.

A reasonable starting point for most businesses is to accept Y, X, A, Z, W, B, P, D and M, decline N and C, and route U, R, S, G and I to review rather than an automatic decline.

Look at what the mismatch is protecting you from

AVS is a weak fraud signal on its own. It confirms that whoever is typing knows the billing address. It does not confirm they hold the card. Card code verification, 3D Secure and velocity rules all do more work. If you are declining a meaningful share of real orders to catch a small number of fraudulent ones, run the numbers before you assume the trade is worth it.

If fraud is the real concern, there are stronger controls worth having in place than an address filter.

Then look at what it is costing you

This is the part that does not appear in anyone else’s explanation of AVS, and it is the part that shows up on your bill.

Every AVS check is billable

An address verification request is a separate message to the card networks, and processors bill for it. The charge is usually a few cents, listed on the statement as an AVS fee, address verification fee or something similar. A few cents is not the problem. The volume is.

Consider what a mismatch actually generates. The customer submits the order and the address check runs. The transaction is declined. The customer corrects the address and submits again, and a second check runs. They mistype the postal code and try a third time. One completed sale, three billable authorizations and three billable address checks.

Now apply that across a checkout where a meaningful share of customers mismatch on the first attempt, on a card not present business running thousands of transactions a month. The fee is small and the count is large, which is exactly the shape of charge that never gets questioned.

Two things worth checking on your own statement:

• Are you being billed for verification twice on the same transaction? Some setups run an address check and a card code check as separate billed events on a single authorization. Both may be legitimate. Both being billed at a marked up rate is a different question.
• Are you being billed for checks that never ran? A U, R or S response means the issuer did not perform a comparison. Whether your processor still bills for the attempt is worth asking in writing.

We have written up the fee side in detail, including how it appears on a statement and what to ask your processor about it, on the AVS fee page. The card code verification fee works the same way and is often billed alongside it.

Where AVS fits in the wider picture

If you are seeing a lot of mismatches, it is usually a symptom of a card not present business with a checkout that is asking customers for the wrong address, or a gateway configured by someone who no longer works there. Neither is a fraud problem. Both cost money, once in lost orders and again in fees.

If the terminology is getting in the way, the credit card processing glossary defines the rest of it in plain English.

The short version

• An AVS mismatch is a description, not a decline. Someone downstream chose to decline it.
• Only the street number and the postal code are compared. Nothing else.
• U, R, S, G and I are not mismatches. No check took place.
• Most mismatches are the wrong address typed by a real customer, not fraud.
• Every check and every retry is a billable event on your merchant statement.

Find out what yours is costing

If you want to know what address verification is actually costing your business, it is on your statement, buried in the per item charges. We read those for a living. Send us a recent statement and we will tell you what you are paying, what is duplicated and what should not be there at all.

Request a free audit, or read more about how a processing audit works.