Give this fortnightly pay calculator one date you are paid on and it generates every pay date for that calendar year, flags the months that contain three paydays, and tells you whether the year is a 26 or a rarer 27 pay-period year.
Why 26 and occasionally 27
26 pay periods of 14 days is 364 days, one short of a common year and two short of a leap year. Those leftover days accumulate until an extra pay date is pushed into a single calendar year, producing 27. It is arithmetic rather than generosity: for salaried staff the annual total is usually unchanged and each cheque is proportionally smaller. Full detail in 26 vs 27 pay periods.
Fortnightly is not semimonthly
Semimonthly means twice a month — 24 payments a year on fixed dates such as the 15th and the last day. Fortnightly means every fourteen days — 26 payments on a fixed weekday. They are different cycles with different cash-flow shapes, and "biweekly" is used loosely for both, which is why contracts should avoid the word. See fortnightly vs biweekly vs semimonthly.