How much is the American Express Green card's over limit fee?

The Amex Green card does not have an over limit fee. Amex might allow you to go over the limit when making a purchase, although it is not guaranteed. If you’re approved to go over the limit, you might be required to make a pre-payment before the purchase or before the balance due date. The exact amount of the pre-payment will be disclosed to you prior to completing the transaction.

Because the card has a “No Preset Spending Limit” feature, it is difficult to pinpoint the exact spending limit that you have. The spending power may fluctuate from month to month, based on your spending patterns, payment history and so on. If you plan on making a large purchase with your Amex Green card, you can use the “Check Spending Power” feature to see if the charge will be approved. You can access that feature from your online account.