In Polish labor law, the salary due but not received due to illness is used for calculating the thirteenth month payment, not the actual amount received.
Thirteenth Month Calculation Basis
For December 2025 salary included in the thirteenth month basis, the amount should be taken as due, meaning reduced by salary for absence due to illness from December 29 to 30.
Work Period Requirements
When determining if an employee qualifies for the thirteenth month, only actual work periods are considered. Simply being employed is not sufficient.
Leave and Absence Policies
When calculating service length for the benefit, justified absences are not counted except for annual leave, which is treated the same as performing work.
Special Cases for Additional Remuneration
The right to additional annual pay without working at least 6 months only applies to special circumstances specified in Art. 2 sec. 3 of the Act on Annual Remuneration, which doesn’t apply to this situation.



