What is the real cost of a restaurant employee beyond salary?

The salary is only part of it. The fully-loaded cost per head also carries the visa and medical, mandatory health insurance, recruitment, often accommodation and transport, training, and the end-of-service entitlement that accrues over time. Budgeting only the basic wage routinely under-states the true labour cost by a meaningful margin — which is why a labour plan built on salaries alone tends to break once the real costs land.

From Restaurant Staffing Costs: Visas, WPS and the Real Price Per Head — the full reading, with the method behind this answer.