Yes, Square accepts American Express cards both in-person and online

Square's payment system processes American Express cards through its standard card reader and online checkout tools. When a customer pays with an Amex card at a Square terminal or through a Square online store, the transaction goes through the same way it does for Visa or Mastercard — no separate setup or special request is needed.

Square treats Amex the same as other major card networks. Your customer can tap, insert, or swipe an Amex card, and it will process. If you use Square Online for invoices or a web store, Amex cards work there too. The card networks handle the transaction on their end; Square's role is to route it to the right processor.

Key Takeaways

  • Square accepts Amex cards at all payment points — in-person terminals, online checkout, and invoices — without any extra setup.
  • Amex transactions process through the same Square reader and software as Visa and Mastercard.
  • Square's interchange rates and processing fees for Amex may differ from other card types, so check your pricing agreement for the exact cost per transaction.
  • If an Amex card is declined, the reason is usually the cardholder's bank or Amex's fraud system, not Square's acceptance of the network.

How Amex cards process through Square

When an Amex cardholder uses your Square reader or checkout, Square sends the transaction data to its payment processor, who routes it to American Express. Amex then either approves or declines the transaction based on the cardholder's account and fraud rules. Square does not decide whether to accept Amex — that decision is made by the card networks and your payment processor.

The physical process is identical to other cards. A customer can tap a contactless Amex card, insert a chip card, or swipe a magnetic stripe. Square's reader recognizes the card type and processes it accordingly. No merchant action is required to "turn on" Amex acceptance; it is built into every Square account.

Amex fees and pricing on Square

Square charges different rates for different card types. American Express typically carries a higher interchange rate than Visa or Mastercard, which means your per-transaction cost will be higher when an Amex card is used. The exact rate depends on your Square pricing plan and your industry.

You can see your Amex rate in your Square Dashboard under Settings > Pricing. Square publishes its standard rates, but some merchants negotiate custom pricing based on sales volume or industry. If you process a high volume of Amex transactions, it is worth asking Square about your current rate to understand your actual cost.

What happens if an Amex card is declined

If a customer's Amex card is declined at your Square terminal, the decline code appears on the screen. Common reasons include insufficient funds, a card that has expired, fraud detection by Amex, or a card that is not active. The decline is not because Square rejects Amex — it is because Amex or the cardholder's bank rejected the specific transaction.

When a card is declined, ask the customer to contact their bank or Amex directly to find out why. They may need to verify the transaction, update their card, or use a different payment method. Square cannot override a decline from the card network.

Amex on Square Online and invoices

If you use Square Online to sell products or services, Amex cards work in your checkout without any extra configuration. Customers see Amex as a payment option alongside Visa and Mastercard. The same applies to Square Invoices — when you send an invoice link to a customer, they can pay with Amex through the embedded payment form.

Square's online payment forms are PCI-compliant, meaning they meet security standards for handling card data. Amex card information is encrypted and never stored on your servers, so you do not have to worry about storing sensitive payment data yourself.

International Amex cards and Square

Square accepts Amex cards issued outside the United States, though the processing rules may vary slightly depending on the card's country of origin and the cardholder's bank. Some international Amex cards have additional fraud checks or currency conversion rules that can cause a decline even if the card is valid.

If you regularly serve international customers, you can check your Square Dashboard to see which countries and card types generate the most declines. This information helps you understand whether a pattern exists or if declines are isolated to specific customers or regions.

Frequently Asked Questions

Do I need to do anything special to accept Amex on Square?

No. Amex acceptance is automatic on every Square account. You do not need to enable it, sign a separate agreement, or change any settings. If you have a Square reader or online checkout, you already accept Amex.

Why is my Amex rate higher than my Visa rate?

American Express typically charges higher interchange fees than Visa or Mastercard. Square passes these costs to you as a higher per-transaction rate. The exact difference depends on your industry and Square pricing plan. Check your Dashboard under Settings > Pricing to see your current Amex rate.

Can a customer pay with Amex if they use a different payment method?

Yes. Amex cards work anywhere Square accepts cards — in-person, online, or through invoices. There is no restriction on which card type a customer can use. If an Amex card is declined, the customer can try a different card or contact their bank.

What if my customer's Amex card keeps getting declined?

The decline is coming from Amex or the cardholder's bank, not from Square. Ask the customer to call their bank or Amex to find out why the card is being rejected. Common reasons include fraud alerts, expired cards, or insufficient funds. Once they resolve the issue with their bank, the card should work.