A rolling year is a period of 12 months that begins and ends on a set day. Rolling years are sometimes used by government agencies and corporations.
Companies use rolling years to mark an employee's start date anniversary to calculate when he or she is eligible for health benefits and to calculate benefits, such as family medical leave. In the business world, rolling years are calculated in the same way for all employees, no matter a person's rank in a company.
A rolling year may not coincide with a fiscal year or a calendar year because their start dates may be different. Calendar years often include leap years, and fiscal years are identical for around 65 percent of publicly traded companies around the world.