Tipping a London Black Cab driver is common practice but is never considered a mandatory obligation. The general rule of thumb for locals is to "round up" the fare to the nearest pound or two. For example, if the meter shows £18.20, it is standard to give the driver £20.00 and tell them to "keep the change." If you are a visitor or have received exceptional service—such as the driver helping with heavy luggage or navigating through intense traffic to get you to the station on time—a tip of around 10% is considered very generous and is highly appreciated. Unlike ride-share apps where you tip after the ride is over, in a black cab, the tip is usually settled during the payment process. If you are paying by card via the terminal in the back of the cab, the screen will often give you the option to add a percentage tip (10%, 15%, or 20%) or a custom amount. Because black cab drivers must pass the grueling "Knowledge" exam and are considered highly skilled professionals, the tip is seen as a gesture of respect for their expertise and the premium service they provide compared to standard private-hire vehicles.