Thirteenth month salary
The thirteenth month’s salary is an additional component of pay to which there is no statutory entitlement; it arises from the individual contract, a collective agreement or company practice, and it is fully subject to contributions and tax.
Definition
On joining or leaving mid-year it is owed pro rata unless otherwise agreed. That pro-rata calculation is the most frequent point of dispute on termination — and the reason the agreement on due date and share belongs in the contract.
It must be distinguished from a bonus: a bonus is voluntary and can be tied to conditions. Paid in the same way over years, it can give rise to an entitlement.
Where to read it
What the software must be able to do
What is needed is the pro-rata calculation for partial years, the accrual across the year, and correct treatment in holiday and overtime rates. Programs that know the thirteenth only as a one-off payment in December calculate leavers wrongly.
Checked Aug 2026
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