Credit card expiration dates - Inclusive or exclusive?

Question

It took me a couple of minutes to find a site that I could source for this.

The card is valid until the last day of the month indicated, after the last [sic]¹ day of the next month; the card cannot be used to make a purchase if the merchant attempts to obtain an authorization. - Source

Also, while looking this up, I found an interesting article on Microsoft's website using an example like this, exec summary: Access 2000 for a month/year defaults to the first day of the month, here's how to override that to calculate the end of the month like you'd want for a credit card.

Additionally, this page has everything you ever wanted to know about credit cards.

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1. This is assumed to be a typo and that it should read "..., after the first day of the next month; ..."

If you are writing a site which takes credit card numbers for payment:

1. You should probably be as permissive as possible, so that if it does expire, you allow the credit card company to catch it. So, allow it until the last second of the last day of the month.
2. Don't write your own credit card processing code. If^H^HWhen you write a bug, someone will lose real money. We all make mistakes, just don't make decisions that turn your mistakes into catastrophes.

Have a look on one of your own credit cards. It'll have some text like EXPIRES END or VALID THRU above the date. So the card expires at the end of the given month.

In my experience, it has expired at the end of that month. That is based on the fact that I can use it during that month, and that month is when my bank sends a new one.

According to Visa's "Card Acceptance and Chargeback Management Guidelines for Visa Merchants"; "Good Thru" (or "Valid Thru") Date is the expiration date of the card:

A card is valid through the last day of the month shown, (e .g ., if the Good Thru date is 03/12,the card is valid through March 31, 2012 and expires on April 1, 2012 .)

It is located below the embossed account number. If the current transaction date is after the "Good Thru" date, the card has expired.