karensavdrag

A deduction from your sick pay that works like an excess. Rather than losing the whole first day, the employer deducts an amount equal to 20 percent of the sick pay you would receive in an average week.

In practice this often means that the first day of an illness is unpaid for someone who works full time, while the deduction is spread differently for people with irregular hours. It applies again if you fall ill anew, but there are rules that limit how many deductions you can have within a period.

Försäkringskassan's pages for employers explain how it is calculated.