"Capping" on an Oyster card (or a contactless payment device) is a feature by Transport for London (TfL) that ensures you never pay more than a certain amount for your travel in a single day or week. Once your individual "pay-as-you-go" fares reach a certain threshold—the Daily Cap—all subsequent journeys on the Tube, DLR, London Overground, Elizabeth Line, and buses within those specific zones are free for the rest of the day. For example, in early 2026, the daily cap for Zones 1–2 is approximately £8.90. There is also a Weekly Cap that runs from Monday to Sunday, which limits your total spend to the price of a 7-Day Travelcard. This system is designed to provide the "best value" automatically; you don't need to choose a pass in advance, as the system tracks your taps and stops charging you once the cap is hit. To ensure the cap is applied correctly, you must always use the same card or device to "tap in and out" throughout your entire day of travel.