Originally Posted by
Guillou
As the others have already mentioned you will generally fine without any cash as long as you have a MC or Visa. There are many places that do not accept Amex. Some few exceptions where cash might actually be needed is a separate cloakroom at a nightclub or a hot dog stand on the street. However, even most of these take cards.
Hot dog stands in Denmark tend to take cards
In the unlikely case that you hit a place that does not take them just move on to the next one. Bus drivers only take cash, so either install a ticket app, or route yourself to buy tickets in machines (for instance in the airport and at train stations).