A gratuity (also called a tip) is a sum of money customarily tendered, in addition to the basic price, to certain service sector workers for a service performed or anticipated. Depending on the country or location, it may be customary to tip servers in bars and restaurants, taxi drivers, hairstylists, and so on.
Tips and their amount are a matter of social custom and etiquette, and the custom varies between countries and settings. In some locations tipping is discouraged and considered insulting; while in others, tipping is expected from customers. The customary amount of a tip can be a specific range of monetary amounts or a certain percentage of the bill based on the perceived quality of the service given.