A service charge is a sum added to a restaurant or hotel bill, usually calculated as a percentage of the total, to pay the staff for their service. Typically around 10 to 15%, it may be discretionary, meaning the customer can ask for it to be removed, or compulsory, in which case it forms part of the price. It differs from a tip, which the diner gives voluntarily, though in practice the two overlap and cause endless confusion. Policies vary by country: some include service in menu prices by law, others leave it to custom. For staff, how the charge is distributed, whether it reaches them fairly, matters enormously. Diners should check the bill: a service charge plus an expected tip is double-paying.