Calculation depends on how wages are paid. A worker paid monthly is entitled to 15 days' pay for each of the first five years and one month's pay for each subsequent year, capped at one and a half years' pay (art. 51). A worker paid by day, week, hour, or piece gets 10 days' pay per year for the first five years and 15 days per year thereafter, capped at one year's pay (art. 51). Fractions of a year are paid pro rata, and any debts or loans owed are deducted (art. 51).
You receive the full gratuity if the employer ends the contract, if a fixed-term contract expires without renewal, if the contract ends under arts. 48, 49 or 50, or if a female worker ends her contract due to marriage within one year of the marriage (art. 52). Entitlement is calculated on the last wage the worker received (art. 62).
This is general legal information, not legal advice. For advice on your specific situation, consult a lawyer licensed in Kuwait.