is a service charge the same as gratuity

[LeLukas]

A service charge differs from a gratuity (tip) in that it is a mandatory fee set by the business, often applied for large groups or special services, and may be used to guarantee employees a consistent wage. A tip, however, is optional and given at the customer’s discretion to reward good service. While both relate to payment for service, one is required, and the other is voluntary.