Where 12.07% comes from
Most workers are entitled to 5.6 weeks of paid holiday a year. If you work 46.4 weeks and take 5.6 weeks off, 5.6 รท 46.4 = 12.07%. For leave years starting on or after 1 April 2024, irregular-hours and part-year workers build up holiday at 12.07% of the hours they work in each pay period.
Rolled-up holiday pay
For irregular-hours and part-year workers, employers can choose to pay holiday as an extra 12.07% on top of each payslip instead of paying it when you take time off. If they do, it should be shown as a separate line on your payslip.