Copenhagen itinerary: 1, 2 and 3 days

Pick by how much you want to walk and whether a day-trip matters more than a second museum day. Times below are door-to-door in the centre, not including meals.

Start at Nyhavn before 9am, when the canal is quiet and the tour boats are still tied up. Walk the harbour south to Kongens Nytorv, then cut through Strøget to the Round Tower if you want the view. Rosenborg Castle and the crown jewels sit in the King's Garden a few minutes north; the guard marches from Rosenborg towards Amalienborg late morning, which is a free thing to watch.

Afternoon: Christiansborg for the palace and tower, or the National Museum if it is raining. End at Tivoli, which opens in the afternoon and is best after dark. If Tivoli is closed (it is seasonal), swap in a harbour bath or a walk through Christiania and Refshaleøen instead.

Day two is the one locals would pick: rent a bike and ride the harbour ring. Cross to Refshaleøen for the food stalls and the street-food yard, then loop back past Amager and the beach park. This is flat, signposted and about 15 km — an easy half-day.

Spend the afternoon on the museum you skipped on day one, then walk Nørrebro or Vesterbro for dinner. If you want a castle, Rosenborg and Amalienborg are both in the centre; if you want art, the SMK and Glyptoteket are a short walk from the station.

The third day is the one to spend outside the city. Roskilde is the shortest ride and gives you the Viking Ship Museum and the cathedral in one afternoon. Helsingør is longer but pairs Kronborg with the ferry to Sweden. Louisiana at Humlebæk is the art option, on the coast north of the city.

Do not try to do two of these in one day. Each is a half-day minimum once you add the walk from the station and a meal.

Copenhagen is expensive by European standards, and the biggest variable is food. Breakfast at a bakery and one sit-down meal a day keeps the total down; two restaurant meals a day pushes it up fast. Transport is cheap if you walk and bike, and the metro is a flat fare by zone.

Book Tivoli and the big museums online in summer; queues at the gate are the main time sink. The metro runs all night, so a late dinner does not need a taxi. Most of the centre is walkable, and a bike beats both the bus and the metro for anything under 3 km.

If you are coming from the airport, the metro takes about 15 minutes to Kongens Nytorv and runs 24 hours. Buy a multi-zone ticket or a travel card rather than single fares if you are staying more than two days.