Number of working days within a month is considered 30, regardless of the actual number of days the month includes. In other words workdays of January (31 days), February (28 or 29 days) or March (30 days) is the same.
Social Insurance and General Health Insurance Law Number 5510, Article 3-14 reads as follows;
“14) (Amended: 17/4/2008 - 5754/1st Art.) Month: shall mean, for the insurance holders under items (a) and (c) of the first paragraph of Article 4, whose wages are payable on 15th of each month, the time period between 15th of a month and the 15th of the next month, and for other insurance holders, the time period between the 1st of the month and the end of that month, and which is deemed to be thirty days,”