Travelcard Zone 5 is the fifth outward zone of the Transport for London zonal system used for calculating co-ordinated inter-modal Travelcard fares within London. In this zonal system, London is split into six approximately concentric zones for the purpose of determining the cost of a Travelcard. The zones are also used for pricing London Underground and Docklands Light Railway single journeys, but not single journeys undertaken entirely by bus or tram, for which a city-wide flat fare applies. The zones are not usually used for calculating the cost of tickets on National Rail services, but do apply to Travelcards used for such services.