In one sentenceEverything the business actually bears for the employee each month: salary, allowances, its GOSI share, and the accrued part of the end-of-service benefit and leave.
Simply put
The salary written in the contract is not the whole cost. On top of it come the business's GOSI share, what builds up for the employee in end-of-service benefit and leave pay, and other costs such as fees and medical insurance if any.
Know this cost before hiring and before pricing the service or product, so you do not discover that the profit is lower than you expected.
Worked example
A restaurant employs a Saudi employee in his first five years: basic 6,000, housing 1,500 and transport 500 SAR (the example leaves out leave and other fees for simplicity).
Total wage8,000
Business's GOSI share: 11.75% × 7,500881.25
Monthly end-of-service accrual: 8,000 × half ÷ 12333.33
True monthly cost9,214.58 SAR
Formula: Total wage + business's GOSI share + monthly benefit accrual + other costs