Banned Ordinary consumer cards
Since 1 January 2018, neither shops nor webshops may add a fee when a private person pays with a common EU-issued card: Dankort, Visa, Visa Debit, Mastercard and Mastercard Debit. The rule comes from the Danish Payments Act and the EU payment directive (PSD2), and it applies wherever in the EU the card was issued.
Allowed, with limits Business cards and non-EU cards
You may add a fee when the customer pays with a business card, a card issued outside the EU, or a three-party scheme such as American Express or Diners. But the fee may not exceed your actual cost per transaction. You cannot make money on it.
Good to know VAT and general fees
When a fee is allowed, it follows the goods: if what you sell carries VAT, the fee is charged including VAT. You may also add a general handling fee, but only if it is the same for every payment method, card and cash alike.
Your own fees What you pay, either way
Whatever the rules, you still pay a fee to accept cards. See where that fee goes, and understand your own statement, with the two tools below.